When comparing Allegro vs PureBasic, the Slant community recommends Allegro for most people. In the question“What are the best 2D game engines?” Allegro is ranked 12th while PureBasic is ranked 40th. The most important reason people chose Allegro is:
The Allegro community has produced a lot of great tutorials and resources. Allegro [Wiki](https://wiki.allegro.cc/index.php?title=Main_Page), Mike Geig's Allegro [Tutorials](http://fixbyproximity.com/2d-game-development-course/), Rachel Morris' [Tutorials](https://www.youtube.com/watch?v=E4RqHtEAAds), CodingMadeEasy's [Tutorials](https://www.youtube.com/playlist?list=PL6B459AAE1642C8B4&feature=plcp).
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Supports desktop and mobile
Support for Windows, Mac OS X, Linux, iPhone, and Android

Pro Good engine architecture
Allegro is well designed, easy to use and has many useful features.
Pro Good documentation and lots of tutorials
Since it has been in development since mid-90s with hundreds of people contributing to both the engine and documentation, it has all of its bases covered when it comes to standard support.

Pro Per-platform library optimization
Allegro uses DirectX for Windows, and OpenGL for other targets.
Pro Freedom to implement your own game engine
You are not bound to the limits of existing game engines, and you can actually implement your own engine.
Pro Standalone executables
Can create single file executables without the need to install other libraries, run time environments, etc.
Pro The syntax is very beginner-friendly
Pro Same code on Windows, OS X and Linux
Same code can be compiled natively, without any interpreter for OS X, Windows or Linux, using the native GUI toolkit of the OS
Pro Many integrated features
Many libraries available without additional installations : 2D & 3D, database, network, sound, xml, JSON, http...
Pro Allows to program at a lower level than most alternatives
Pro Lifetime license
Pay once, use forever.
Pro Constantly updated
Pro Supports ARM in addition to x86, AMD64 and others
Pro Can compile to plain C code
Pro Grest user community / forums with the developer very active
Cons
Con Learning curve for hobbyist developers
Hobbyist developers coding alone may experience a learning curve with Allegro of about 200 hours (if you are rusty on C++). To learn quickly, see Mike Geig's tutorials at Fix By Proximity. This learning curve may be fine if you are considering going professional, but are still unsure.
For hobbyist developers not planning on going professional, you may want to look into a complete 2D game engine, rather than a coding library. For example, there are "non-coding" engines that provide support for coded plugins or scripting. But, if you are a dedicated hobbyist planning to use Allegro as your coding library of choice, you can still develop great games as a hobbyist.
Con Isn't great for C++
If you are a fan of object oriented programming, and want to use this library, then the chances are that you are going to be creating a lot of wrappers for functions in this library.
In short, if you're a C++ person, it could be recommended to check out SFML instead.
Con Limited free version
Free version is limited to 800 lines and can not create DLL's.
Con Some bugs are present on the Linux platform
Con Slightly bogged syntax
Sometimes the syntax bogs down, just a little with long procedure names and such. A truly minor issue.
Con Not RAD
Not a RAD environment.
