When comparing Vala vs V, the Slant community recommends V for most people. In the question“What are the best statically typed, compiled, memory safe programming languages?” V is ranked 3rd while Vala is ranked 9th. The most important reason people chose V is:
Compile app to run on different OSes.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Rich GTK Support
Vala developed by Gnome Foundation.
Pro Fast
Underneath there is C. It makes some stuff easier to write than it would be with plain C code.
Pro Easy Syntax
Vala is syntactically similar to C# and includes several features such as: anonymous functions, signals, properties, generics, assisted memory management, exception handling, type inference, and foreach statements
Pro C compatible API (and ABI)
C programs can use libraries written in Vala, and vice versa.
Pro Good documentation
There is Valadoc and most of the libraries have Devhelp packages.
Pro Well-integrated with C language
Vala itself is compiled to C, therefore it can use the vast ecosystem of C language, with least effort.
Pro Stable ABI
You can write a library with ABI stability.
Pro A general purpose language
Vala is compiled to C and only requires GLib - or even nothing (posix profile)
Pro Cross-platform
Compile app to run on different OSes.
Pro Sum types
V has sum types.
Pro GUI support
V comes with (simple) GUI support out of the box.
Pro Clear syntax
Highly understandable language.
Pro Safety
V is very safe.
Pro Fast like C
V is easier than C and fast like C.
Pro Closures
V has closures, which gives the user additional options and usefulness.
Pro Generics
V has generics.
Pro Supports concurrency and channels
Can run functions concurrently that communicate over channels.
Pro C Interop
Can import C libraries, structs, and headers.
Pro Fast compile times
Compiles programs fast, less waiting around, so more productive and fun.
Pro Lambdas
Supports using lambdas, which helps write more concise code without having to use so many lines.
Cons
Con Very few resources allocated to the language
Only a single person is working on Vala full time. Gnome Foundation isn't allocating sufficient resources to properly maintain Vala.
Con A very naïve approach to the real problem
Vala just adds more complexity to the game. No real benefits in using a 'programming language emulator' for UI code, you may think it adds to productivity but it's just a way to make the problem last longer, reinventing the wheel everytime and worse.
Con Very limited adoption
Vala isn't used in areas other than GTK development, and no major business has adopted the language.
Con Not a general purpose language
Can't use Vala in multiple software development areas.
Con Very limited tooling
Though using Gnome Builder, you can debug it easily.
Con Heavy reliance on GObject
Heavy reliance on GObject types, although Vala can be used without GObject. (posix profile)
Con Not well documented
It already has tons of documentation, even a book about Vala.https://leanpub.com/vala https://wiki.gnome.org/Projects/Vala/Documentation
Con No stable version
No stable version of Vala released for over a decade so far. Means that Vala isn't production ready.