When comparing Haskell vs Go, the Slant community recommends Go for most people. In the question“What is the best programming language to learn first?” Go is ranked 2nd while Haskell is ranked 26th. The most important reason people chose Go is:
The language is designed in a manner that seems logical. Syntax is simplified to reduce burden on the programmer and compiler developers.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Highly transferable concepts
Haskell's referential transparency, consistency, mathematics-oriented culture, and heavy amount of abstraction encourage problem solving at a very high level. The fact that this is all built upon little other than function application means that not only is the thought process, but even concrete solutions are very transferable to any other language. In fact, in Haskell, it's quite common for a solution to simply be written as an interpreter that can then generate code in some other language. Many other languages employ language-specific features, or work around a lack of features with heavy-handed design patterns that discourage abstraction, meaning that a lot of what is learned, and a lot of code that is needed to solve a particular problem just isn't very applicable to any other language's ecosystem.
Pro Forces you to learn pure functional programming
It is pure and does not mix other programming paradigms into the language. This forces you to learn functional programming in its most pure form. You avoid falling back on old habits and learn an entirely new way to program.
Pro Open source
All Haskell implementations are completely free and open source.
Pro Mathematical consistency
As Haskell lends itself exceedingly well to abstraction, and borrows heavily from the culture of pure mathematics, it means that a lot more code conforms to very high-level abstractions. You can expect code from vastly different libraries to follow the same rules, and to be incredibly self-consistent. It's not uncommon to find that a parser library works the same way as a string library, which works the same way as a window manager library. This often means that getting familiar and productive with new libraries is often much easier than in other languages.
Pro Referentially transparent
Haskell's Purely Functional approach means that code is referentially transparent. This means that to read a function, one only needs to know its arguments. Code works the same way that expressions work in Algebra class. There's no need to read the whole source code to determine if there's some subtle reference to some mutable state, and no worries about someone writing a "getter" that also mutates the object it's called on. Functions are all directly testable in the REPL, and there's no need to remember to call methods in a certain order to properly initialize an object. No breakage of encapsulation, and no leaky abstractions.

Pro Hand-writeable concise syntax
Conciseness of Haskell lets us to write the expression on the whiteboard or paper and discuss with others easily. This is a strong benefit to learn FP over other languages.
Pro Very few language constructs
The base language relies primarily on function application, with a very small amount of special-case syntax. Once you know the rules for function application, you know most of the language.
Pro Quick feedback
It's often said that, in Haskell, if it compiles, it works. This short feedback loop can speed up learning process, by making it clear exactly when and where mistakes are made.
Pro Functions curry automatically
Every function that expects more than one arguments is basically a function that returns a partially applied function. This is well-suited to function composition, elegance, and concision.
Pro Easy to read
Haskell is a very terse language, particularly due to its type inference. This means there's nothing to distract from the intent of the code, making it very readable. This is in sharp contrast to languages like Java, where skimming code requires learning which details can be ignored. Haskell's terseness also lends itself to very clear inline examples in textbooks, and makes it a pleasure to read through code even on a cellphone screen.
Pro Popular in teaching
Haskell is really popular in universities and academia as a tool to teach programming. A lot of books for people who don't know programming are written around Haskell. This means that there are a lot of resources for beginners in programming with which to learn Haskell and functional programming concepts.
Pro Easy syntax for people with a STEM degree
Since the basic syntax is very similar to mathematics, Haskell syntax should be easy for people who have taken higher math courses since they would be used to the symbols used in maths.
Pro Powerful categorical abstractions
Makes categorical higher order abstractions easy to use and natural to the language.

Pro Simplified C-like syntax that is as easy to read and write as Python
The language is designed in a manner that seems logical. Syntax is simplified to reduce burden on the programmer and compiler developers.
Pro Great team working behind it
Go has a solid team of engineers working on it (some of the best networking engineers in the world are working on Go). Up until now, the great engineering of the language has compensated for its lack of power.

Pro Easy to install and configure; simple to compile software
Go software can be immediately installed, regardless of your operating system, package manager, or processor architecture with the go get command. Software is compiled statically by default so there is no need to worry about software dependencies on the client system. Makefiles and headers are no longer necessary, as the package system automatically resolves dependencies, downloads source code and compiles via a single command: go build
.

Pro Programmers don't have to argue over what 10% subet of the language to implement in their software project
The language promotes programming in a specific idiomatic style, which helps keep every programmer on the same page.

Pro Supports 'modules' in the form of packages
Every Go source file contains a package line that indicates which package a file belongs to. If the name of the package is 'main', it indicates that this is a program that will be compiled into a binary. Otherwise, it will recognize that it is a package.

Pro Demonstrates a unique, simple concept to object-oriented programming
All types are essentially objects, be they type aliases or structs. The compiler automatically associates types to their methods at compile time. Those methods are automatically associated to all interfaces that match. This allows you to gain the benefits of multiple inheritance without glue code. As a result of the design, classes are rendered obsolete and the resulting style is easy to comprehend.
Pro Great language for building networking services
Go was started as a systems language but now it has fully committed in the niche of networking services. This has been a brilliant move by Go because it allows them to capitalize on the immense talent of the Go engineering team (who are in the most part network engineers).
In a world dominated by Java EE and slow scripting language, Go was a breath of fresh air and it continues to be one of the most powerful languages if you want to build networking services.

Pro Exceptionally simple and scalable multithreaded and concurrent programming
Goroutines are "lightweight threads" that runs on OS threads. They provide a simple way for concurrent operations — prepending a function with go
will execute it concurrently. It utilizes channels for communication between goroutines which aids to prevent races and makes synchronizing execution effortless across goroutines. The maximum number of OS threads goroutines can run on may be defined at compile time with the GOMAXPROCS
variable.

Pro The go compiler compiles binaries instantly — as fast as a scripting language interpreter
Compiled binaries are fast — about as fast in C in most cases. Compiles on every OS without effort — truly cross-platform compiler. As a result of the fast compilation speed, you can use the gorun program to use go source code as if it was a scripting language.
Pro Performance is on the order of C and Java
Go is blazing fast, but easier to write than Python, JS, Ruby, or many other dynamic languages.
Pro Jobs available
You can find a Job knowing Go. Which is more than can be said with many other languages.

Pro API documentation is rich in content; easy to memorize
Only features deemed critical are added to the language to prevent cruft from working its way into the language. The language is small enough to fit inside one's head without having to repeatedly open documentation. Documentation is hosted on an official webpage in a manner that is simple to read and understand.

Pro Supports functional programming techniques such as function literals
This naturally also supports first class and high order functions, so you may pass functions as variables to other functions.

Pro Multiple variables may be assigned on a single line
This conveniently eliminates the need to create temporary variables.
Fibonacci example: x, y = y, x+y

Pro Built-in unit testing
The idiomatic approach to writing a Go software project is to perform test-driven development with unit testing. Every source code file should have an associated *_test.go
file which tests functions in the code.

Pro Provides tools for automatically formatting code for your entire software project
This helps keep every programmer on the same page in a project and eliminates arguments over formatting styles.

Pro Automatically generates API documentation for installed packages
Godoc is provided to automatically generate API documentation for Go projects. Godoc also hosts its own self-contained web server that will list documentation for all installed packages in your Go path.

Pro Supports splitting source code into multiple files
As long as every source code file in a directory has the same package name, the compiler will automatically concatenate all of the files together during the compilation process.

Pro Syntax for exported code from a package is simplified to be less verbose than other languages
Any variable, type and function whose name begins with a capital letter will be exported by a project, while all other code remains private. There is no longer a need to signify that a piece of code is 'private' or 'public' manually.
Cons
Con Language extensions lead to unfamiliar code
Haskell's language extensions, while making the language incredibly flexible for experienced users, makes a lot of code incredibly unfamiliar for beginners. Some pragmas, like NoMonomorphismRestriction, have effects that seem completely transparent in code, leading beginners to wonder why it's there. Others, like ViewPatterns, and particularly TemplateHaskell, create completely new syntax rules that render code incomprehensible to beginners expecting vanilla function application.
Con Difficult learning curve
Haskell lends itself well to powerful abstractions - the result is that even basic, commonly used libraries, while easy to use, are implemened using a vocabularly that requires a lot of backround in abstract mathematics to understand. Even a concept as simple as "combine A and B" is often, both in code and in tutorials, described in terms of confusing and discouraging terms like "monad", "magma", "monoid", "groupoid", and "ring". This also occasionally bears its ugly head in the form of complicated error messages from type inference.
Con Package manager is unstable & lacking features
Cabal (There are other choices but this is the most popular) can not uninstall a package. Also working at a few locations it is difficult to have the same environment for each one be the same.

Con You have to learn more than just FP
Haskell is not only a functional language but also a lazy, and statically typed one. Not only that but it's almost necessary to learn about monads before you can do anything useful.
Con Symbols everywhere
Haskell allows users to define their own infix operators, even with their own precedence. The result is that some code is filled with foreign looking operators that are assumed to be special-case syntax. Even for programmers who know they're just functions, operators that change infix precedence can potentially break expectations of how an expression is evaluated, if not used with care.
Con Obscure ugly notation
0 = 1
Using "=" like this: <code>
-- Using recursion (with pattern matching)
factorial 0 = 1
factorial n = n * factorial (n - 1) </code> Example from https://en.wikipedia.org/wiki/Haskell_(programming_language)
is quite simply annoying aesthetics.
Con Documentation for most packages is short and lacking
A few Haskell packages are well documented but this is the exception, not the rule.
Most of the time a list of function signatures is what passes for documentation.
Con Too academic, hard to find "real world" code examples
Con You need some time to start seeing results
Haskell's static typing, while helpful when building a project, can be positively frustrating for beginners. Quick feedback for errors means delaying the dopamine hit of code actually running. While in some languages, a beginner's first experience may be their code printing "Hello World" and then crashing, in Haskell, similar code would more likely be met with an incomprehensible type error.
Con Lazily evaluated
Haskell's lazy evaluation implies a level of indirection - you're not passing a value, you're passing a thunk. This is often difficult to grasp not just for beginners, but for experienced programmers coming from strictly evaluated languages. This also means that, since for many, strict evaluation is their first instinct, initial expectations of a function's performance and complexity are often broken.
Con Only pure functional programming
Not proper functional programming but a subset of the style called pure functional programming.
Con Curried type signatures obfuscate what were the in and out types originally
Con Golang controlled by Google
Solves Google problems, which might not be your or the majority of user's problems. Was created for the benefit and purposes of Google, so is less flexible in language direction and options.
Con Hard to abstract even the simplest notions
Go is famously regarded as very simple. However, this simplicity becomes problematic in time. Programmers who use Go find themselves over and over again writing the same thing from a very low point of view. Domains not already served by libraries that are easy to glue are very difficult to get into.
Con Forces K&R style and won't allow Allman style
Golang developers were extremely short-sighted and biased by forcing the K&R style, which should never have happened. Basically kicking Allman style users out of their language.
Con Doesn't have true enums
Golang does weirdness with const versus having real enums, like other languages. This reflects the stubbornness and shortsightedness of the core developers, similar to the issue with generics, where it was denied that it was needed until it became too obvious that it should have been added years ago.
Con Does not have sum types
Makes it harder to have functions of different parameters types in a non OOP language. Thus messy generics and interfaces, and more confusion, where sum types could have solved a number of issues.
Con It appears Google uses position to snuff out or suppress other languages
Newer languages that could threaten Golang (or other Google controlled languages) appear to have suppressed search results on Google and YouTube. Dangerous situation where large company can manipulate user choice and market share. The freedom to freely choose and user rights need to be protected.
Con Designed to make the programmer expendable
Go was designed for large team projects where many contributors may be incompetent. That Go can still get things done under these conditions is a testament to its utility in this niche. Go's infamously weak abstraction power is thus a feature, not a bug, meant to prevent your teammates from doing too much damage. This also means any team member can be easily replaced by another code monkey at minimum cost. Good for the company, bad for you. The more talented programmers, on the other hand, will be very frustrated by having one hand tied behind their back.
Con Easy to shadow variable
Due to single character only difference, declare and assign statement can easily shadow variable from outer scope unconsciously. Example:
err := nil
if xxx {
err := somefunctionthatreturnsanerr
}
return err // always return nil
Con No forms designer
Those who are used to Visual Studio can feel the lack of a forms designer for rapid development.
Con Bizarre syntactic choices like a unique date format.
Con Changing visibility requires renaming all over the code
Con Lacks support for immutable data
Only way to prevent something from being mutated is to make copies of it, and to be very careful to not mutate it.
Con Performance slowdown because of indirect calls and garbage collection
Practically no meaningful Go application can be written without indirect function calls and garbage collection, these are central to Go's core infrastructure. But these are major impediments to achieving good performance.
Con Implementation of interfaces are difficult to figure out
Finding out what interfaces are implemented by a struct requires a magic crystal ball. They are easy to write, but difficult to read and trawl through.
