My "Built By ATI" 8500LE 128MB has BEAUTIFUL image quality... 2d and 3d. This is the best my 2d has ever looked... period. I could notice a huge difference, having seen and extensively used Intel graphics, TNT, Geforce 2, 3, and 4. Nvidia makes no advances in the 2d field as they move along. They really need to focus a bit when the next iteration goes together.
The BUILT BY ATI cards are going to give you crystal clear sharp 2d, with the only bottleneck being possibly your monitor.
OEM is a dumb idea in by book.
In almost all cases.