I tweaked my ubuntu 11.04 and replaced the default window manager with Gnome 3. It took a while to get used to it but eventually I like it a lot. I think part of the reason ubuntu is turning to unity instead of the old gnome2 is that the new gnome represents such a drastic shift away from the old gnome2, which is no longer under active development.
The overall experience is positive. I expect the next release will get rid of the few annoyance such as the lack of easy-to-use configuration tool to tweak things like screensaver, sound, etc.