When comparing CRM32Pro SDK vs FlatRedBall, the Slant community recommends FlatRedBall for most people. In the question“What are the best 2D game engines?” FlatRedBall is ranked 44th while CRM32Pro SDK is ranked 91st. The most important reason people chose FlatRedBall is:
Just check the commit frequency on github :) https://github.com/vchelaru/FlatRedBall/commits/master Plus Victor takes community input seriously and is known to shift around priorities based on the pressing needs of the community
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Great tools included
EditorDPF: resource editor for managing images, tiles, sprites, sounds, etc. of your game
MSTE: tile-based parallax scrolling engine with support to Tiled Qt .TMX files
SetupProject: customized configuration system.

Pro Cross-platform
CRM32Pro works on Windows, Linux and MacOS X.

Pro Open source and free
CRM32Pro is licensed under LGPL license with full access to the source code on the website.
Pro Continually improving and open source
Just check the commit frequency on github :)
https://github.com/vchelaru/FlatRedBall/commits/master
Plus Victor takes community input seriously and is known to shift around priorities based on the pressing needs of the community
Pro Very easy to use
Simplifies routine tasks such as adding entities and files to the game, or tuning parameters, via the FRB Editor called Glue
Pro Great community
Very active chat on gitter: https://gitter.im/vchelaru/FlatRedBall
Victor (the creator of the engine) is available throughout the day to answer questions and solve any problems that may arise, along with the rest of the community members who are ready to assist in any way they can.
Pro Extensive documentation
http://flatredball.com/documentation/
Very good documentation not only regarding the API details, but also lots of tutorials covering different aspects of using FRB, either on the code-side or on using any of its tools.
Cons
Con Not as beginner friendly
C/C++ skills and general knowledge of SDL and basic game programming is required in order to get all the benefits.
Con The editor's UI looks dated
Although functional, doesn't look as flashy as Unity for example, which may put some people off.
