I was using KDE until it broke me down with its poor networking (you cannot open+save an Openoffice document from/to the network), then I switched to Gnome + Compiz Fusion which is actually quite good but a little bit unstable sometimes (at least with the open source ATI driver).

I watched a video introducing Gnome3 and its new features and read an excellent article about its basics. I gave it a try by installing Fedora15 on my home desktop and laptop.

Certainly, there are some annoyances so I've started to build a "tips and tricks" page - well, probably, I'm not alone with that. :P
There are a dozens of pages asking how to do this or that, and even more collections of tools and tips. Still, I haven't found a comprehensive guide for "transition from Compiz to Gnome".

I've also tried the new Unity from Ubuntu which is also based on Gnome3 but it uses Unity instead of Gnome Shell. I've fould it quite disturbing. Cloning MacOS did not go well for them - or I'm not prepared enough to consume that many changes the've made :)

Gnome3 and Gnome Shell (don't mix up these two) are new and they need to mature, but they definitely worth a try! Useful addons come out day-by-day so it won't take long time Gnome3 becomes a popular graphical shell.