When comparing UDK vs Crystal Space 3D, the Slant community recommends UDK for most people. In the question“What are the best 3D game engines?” UDK is ranked 17th while Crystal Space 3D is ranked 44th. The most important reason people chose UDK is:
UDK has an extremely large toolset that allows creating almost anything without having to use a 3rd party tool or plugin.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Large toolset
UDK has an extremely large toolset that allows creating almost anything without having to use a 3rd party tool or plugin.
Pro Triple A track record
UDK is an engine used by many big name companies for popular games such as the Gears of War series.
Pro Scripting language bindings (via swig) python, perl, tcl
Scripting language biddings are available via swig, supposedly any swig target could be used If you are okay with building, and probably maintaining, the project for your own needs then you may be able to build bindings for your favorite scripting platform.
As noted in a slant "con", there are no binary releases, including no prebuilt bindings.
Pro Cross platform
Runs on all major desktop platforms.
Cons
Con Superseded by Unreal Engine 4
Con DevKit only runs on Windows
Even though UDK can deploy games to run on multiple platforms, including Mac, it does not feature support for development on Mac.
Con Limits games to FPS
UDK was originally developed for the FPS, "Unreal Tournament", and it certainly shows. While UDK is a very powerful engine, it takes quite a bit of work to make it do something other than an FPS.
Con No binary releases.
Expect to compile this from source if your want to play with it.
Ubuntu has a package for it, but that package appears to be missing it's scripting language bindings. I expect the build is also quite old and i fear may be dropped in coming Ubuntu releases.