I like that they stuck with Compiz. Linux is fragmented in no small part due to developers wanting to create shiny new software instead of supporting more boring older software. When that happens we get 100 window managers all with their little quirks and all of them liable to be discarded at the drop of a hat. I mean, just look at this massive list of window managers: http://en.wikipedia.org/wiki/X_window_manager#X_Window_manag...

Despite Compiz's flaws Canonical did the right thing by sticking to and polishing an existing WM instead of creating yet another WM with its own weird flaws and bugs. Plus, I like wobbly windows :)