I think Compiz has reached a state where it has accomplished the needs of the everyday user. I don't think most users are interested in most of the eye-candy stuff that Compiz delivers. They make great Youtube videos but are mostly impractical. I use compiz, but with a minimal setup. I do use translucent borders, drop shadows and a few of the animations (mostly just fade). I'm a GNOME user and I have to admit the main reason I don't use Metacity is because I want new windows to appear in the center of the screen (not the top left corner) and there is no option to do that with Metacity. If/when Metacity chooses to implement that option then I would consider switching to metacity with compositing enabled. Until then Compiz with minimal effects works just nicely.