Gnome3 (Gnome-shell) works perfectly well under natty. I did a Ubuntu-minimal installtion and started from scratch that way. This is the best way imho. Otherwise you get other, residual stuff from the Unity installtion. It's worth doing if anything to get practice with the terminal commands, and it's fun in to the bargain.
Gnome3.shell has a long way to go before its fully ready to be shipped as default. I know fedroa 15 has it but fedora is meant to be bleeding edge. There aren't enough utilites for it yet but it is perfectly stable to use. If anything I've found it more stable than Unity has been on natty.