I tried Gnome 3 when Fedora 15 came out.
When I discovered that Gnome 3 didn't work properly with two separate X servers (one for my laptop's screen and one for my external screen), I junked Fedora and switched to Linux Mint as they were still using Gnome 2.
Now I see that the latest Linux Mint has switched to Gnome 3 and it still does not work properly with separate X servers! WTF?
I honestly fail to believe that a user like me with two Compiz cubes, one on each screen, is an unusual case. The Gnome 3 devs seems to have been completely blinded by their own hubris.
I'll stick with what I have thanks.