I've used and tested all cards.
Radeon = excellent 2d, excellent 3D image quality, fast but not fastest
V5 = excellent 2d, excellent 3d image, pretty fast, might have more potential with HSR drivers. Best 16bit 3d of the lot. DOES support 16Bit - not sure what the hell the last guy is on about..
GTS = fastest card, but below par 2d. Very good 3d quality but not the best...