I would tend to think it would require some nifty hacks. KDE might not love being without kwin - they are pretty tied together. Compiz 0.8 series works great with xfce though
Compiz works with KDE no problem. I use it, always have, always will. What I don't get is why everyone doesn't use it. IT. IS. The single best window management and compositor ever. Truthfully its the initial reason I switched from Windows way back over 10 years ago I was amazed by the embeded terminal, and the visual effects and the desktop cube. Awesomeness without limits. Its amazing to me that Compiz has not remained the leading application. The most customizable, most eye candy, most productive. Its just great!
Everyone has his/her own taste. Like if I give you a million dollars ( Just imagine ) to buy a car, which one would you buy? Some will say Ferrari , some will go with Rolls Royce , some with Lamborghini etc. It is just a matter of taste.