When comparing Amethyst vs Crystal Space 3D, the Slant community recommends Amethyst for most people. In the question“What are the best 3D game engines?” Amethyst is ranked 26th while Crystal Space 3D is ranked 44th. The most important reason people chose Amethyst is:
Amethyst is published under the MIT license making it open-source and id offered completely free. This allows anyone to give the tiling window manger a try, which is great.
Specs
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Pros

Pro It's free and open-source
Amethyst is published under the MIT license making it open-source and id offered completely free. This allows anyone to give the tiling window manger a try, which is great.

Pro Recently updated and rewritten in Swift.
The application was written in Objective-C, but was recently updated and completely rewritten in Apple's new native language Swift.

Pro Works with keyboard shortcuts, no mouse needed
As it's designed to work closely to how xmonad, Amethyst uses keyboard shortcuts to control the windows being used, meaning no mouse input is necessary. This can make for a faster way to control windows.
Pro Multi-monitor suppport
Pro Has many common layouts to choose from (fullscreen, floating, row, column, wide, etc)
Pro Can switch between tiling and floating mode
Pro Under active development
Pro Configured via UI
No CONFIG file provides security and will avoid making amethyst crash. Instead configured via simple UI
Pro True tiling means never losing track of windows under a huge pile of others
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 Can be buggy at times
Con There are more user friendly window managers available
There are certainly more user friendly window managers available for MacOS, such as Divvy or Moom. Amethyst, however, is more powerful and customizable than the more user friendly options available and therefore may be a better choice for a user looking for more advanced capabilities and customization.
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.
