I use Gnome Shell partially because I don't want compiz. Compiz consumes way too many resources from my computer. Unity is great. No doubt, but it shouldn't be a compiz plugin, it should work the same way Gnome Shell does, not with Compiz.<p>A lot of people complain about customization on both, so I just say: try Awesome WM. This window manager is very easy to use and very simple to customize, it really lives up to its name (awesome).<p>I use both Gnome Shell and Awesome WM on Arch Linux, I like both of them, although I've been using more and more Gnome Shell lately, partially because Gnome 3.4 is almost in the stable repositories, and I am very anxious for it.