I don’t use Unity for numerous reasons. I have written about it extensively. I use KDE with Ubuntu (unfortunately Kubuntu 12.04 seems to be extremely buggy as Gnome apps crash without warning. Liferea will crash the moment you open a link). I will pick Gnome 3 Shell or KDE over Unity any given day also due to the lack of customization. But since there is no ‘official’ Gnome 3 Shell flavor of Ubuntu if I want to use pure Gnome 3 Shell all my options are outside Ubuntu. The good news is later this year Ubuntu will come in a Gnome Shell flavour as well.