When comparing Vala vs Gambas, the Slant community recommends Gambas for most people. In the question“What are the best languages to write a desktop Linux application in?” Gambas is ranked 1st while Vala is ranked 4th. The most important reason people chose Gambas is:
You can't find such a level of easy GUI development in any other language on the Linux platform.
Specs
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 Complete IDE for GUI development
You can't find such a level of easy GUI development in any other language on the Linux platform.
Pro Constantly updated
New features and bug fixes along with performance enhancements.
Pro Easy to get started for someone familiar with VB on Windows
Pro Complete application development suite
Supports GTK and QT along with web. Built in Form building with JIT speed. If you are developing an application targeting Linux only give this a look.
Pro Fast to write apps
Pro Git integration
Integration with GIT in IDE and easy to distribute apps as source package with export as .tar.gz.
Pro Enhanced with a new test suite
Pro Runs on Windows 10 WSL2 environment, reported successful compilation on MacOS
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.
Con Not cross platform
Con The documentation is not the best
Con May have trouble interfacing to C code structs
Managed struct objects in Gambas makes it harder to use with C code structs.
Con Difficult to satisfy runtime requirements
Runtime requirements to run applications written in Gambas are not always easy to satisfy (that is, without installing the whole development environment).
