Count me among them. Slow and buggy. I finally gave up on it and switched my main Ubuntu desktop back to a Gnome "classic" shell/gui.
Still considering jumping entirely to Mepis with a KDE 4.x shell/gui...
I use XFCE myself.
This whole Unity/Gnome 3 debacle is ridiculous. I can’t stand either of them. I’m holding steady with Mint 9 until Cinnamon is released. I tried KDE, but it’s just too bloated and slow. I tried Xfce, but it is too minimalist for my taste. My desktop isn’t ever going to be a tablet and vice versa.