I think many companies see the features (windows flying around in Exposé, brightly colored window management buttons, pulsing status light, etc.) but don't understand that generally Apple doesn't just throw something in for looks and has thoroughly researched and iterated internally on a particular solution.
At the expense of sounding fanatic, generally an Apple feature looks the way it does as a result of its function. (What is the problem: make window management easy. how is that solved: make all open windows easy to see by spreading them out). When other companies attempt to copy, they look at what Apple's solution looks like, not realizing what it _does_. (e.g. Areo Flip 3D: what should it look like: windows flying all over the place. what problem does this solve: ???)