my 'other' option to boot at start (next to sabayon with Gnome3, screenshot two posts above this one): http://www.youtube.com/watch?v=1-Ev8rRalTM
Why Ubuntu AND Sabayon ? Because Unity is the only option to use Gnome3+Compiz with Cube and all effects... and you can still switch to Gnome 3 shell from login options.
In my opinion, gnome 3 shell doesn't add enough to justify the absence of compiz (hotcorners etc)
But I also love Sabayon for other reasons, so I wanted both worlds for now....