Google founds me that when I search gallium3d and nouveau:
I mean yes radeon is further but they are more close without any support of nvidia here the feature matrix:
the basic stuff inclusive xv works (for fluently videos) also exa (fast 2d accelleration) even some 3d stuff works. But yes radeon driver is gladly a good step ahead, but soooo much more does the radeon driver not do.
But ok the 3d speed really really sucks in comparsion the radeon driver is a roadrunner: