Comment 8 for bug 839838

OK, Gnome Shell starts, but crashes the second I try to do anything. Gnome Classic (with effects) immediately reverts to fallback mode. I run a couple of screenlets; I disabled these in case that was the culprit. (That turned out to be slightly tricky, since 'Startup Applications' has been removed from the system settings panel. Fortunately, it's still around as a standalone program.)
I guess I could fix things by doing a clean install, but I'm guessing I won't be the only one who tries going the upgrade route.
Right now I can only use Unity 2D or a really buggy Gnome fallback session.