Linux XGL/Compiz

"Compiz brings to life a variety of visual effects that make the Linux desktop easier to use, more powerful and intuitive, and more accessible for users with special needs. Compiz combines together a window manager and a composite manager using OpenGL for rendering. A 'window manager' allows the manipulation of the multiple applications and dialog windows that are presented on the screen. A 'composite manager' allows windows and other graphics to be combined together to create composite images. Compiz achieves its stunning effects by doing both of these functions."

Needless to say everything in the video is being run on advanced graphic cards, however these are the same cards upon which windows vista's aero and Apple's Aqua are based.
You can read the original article and see this video as well as Aero & Aqua demos by clicking this sentence.

Which OS do you find the most advanced?