When comparing pyglet vs Genome2D, the Slant community recommends pyglet for most people. In the question“What are the best 2D game engines?” pyglet is ranked 45th while Genome2D is ranked 46th. The most important reason people chose pyglet is:
Since pyglet is so tightly woven with OpenGL it allows the support of drawing in 3D.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro 3D support
Since pyglet is so tightly woven with OpenGL it allows the support of drawing in 3D.
Pro Cross-platform
Works with Windows, Linux, and OS X.
Pro Written in pure Python
A small advantage, but being a core Python developer, it may be the best to stick to the roots and develop with pyglet as it is able to compile using other Python interpreters.

Pro Lightning fast
It's the fastest gpu-based framework out there for flash. It's beautifully optimised. It has very low rendering latency, low level OpenGL calls that other tech simply cannot do (ie Unity) due to Stage3D, and thus can render a lot more data quicker
Pro Cross-platform mobile, desktop and web
Supports Windows, Mac OS X, Linux, iOS, Android, Web and native Flash.
And with the HTML5 export, it also potentially supports development for the Wii U :)
Pro Haxe!
Haxe is a strictly typed programming language that saves development time but still compiles high performance executables, and can build for tons of different platforms (flash, c++, html5, java, c#, etc.)
Pro Access to direct draw features
Has access to direct draw features so you can make you own rendering structures (scene graphs etc).
Pro Automatic dynamic batching
Automatically batch geometries with dynamic batching techniques (by using constant buffers).
Pro Component based architecture
Cons
Con Small community/popularity
There is a decent amount of documentation and API to go along with pyglet, but in terms of community support there seems to be very little.
Con Lacks documentation
The API documentation is minimal, there's not many tutorials and the ones that are there are very small and only cover the basics. If you want to learn how to properly use it, you have to ask the community or read the source code and figure it out.
Con Not too many games to showcase it
Con Slow development rate
