I bopped around in it for a few minutes on my Atom/Intel graphics EeePC and found it unbearably heavyweight compared to Awesome. I don't know what they are doing wrong, but merely interacting with a bunch of xterms with it was unbearable. Maybe you are just use to it.

It sure feels heavy compared to CDE or twm either, but that's hardly fair.

I think it is eminently fair. It isn't performing a fundamentally different task, but it stutters and burns lower powered machines up.

Radeon opensource drivers are just fine. KDE with composite WM runs smoothly. Sometimes I play heavy games with Wine (Civ4, Stalker...). And did I mention resolution: 3000x1600