I think that this is more to do with just the fact that it's so new and immature that it's going to take a while for things to settle down... I expect that the interfaces the extensions depend on should stabilise fairly soon.
Ubuntu Unity and Gnome Shell on Gnome 3 both seem to take a few weeks to 'get into' I find.
Currently GS on Gnome 3.6 as provided by the Gnome Ubuntu Remix 12.10 has my attention, seems a good fit to my end user like use cases. The only plug-in at present is the one to put the hibernate command back on the power/system settings menu.
I find GS gives me the illusion of being more responsive (perhaps because when invoking the search screen there is no dynamic search going on) and is somehow 'quieter' in operation.