I always thought that both drivers would specialize on different chips, and not overlap as they are doing right now. I was expecting radeon to take care of r400 and lower type hardware, and radeonhd r500 and above. Now with radeon starting to support even the newest cards, I don't see the need for 2 driver sets. The whole AtomBIOS thing seemed like the only real difference (and a rather "philosophical" one at that) between the two, and now with that difference gone, I see even less of a reason for having seperate sets, for basically the same hardware. I guess future performance differences (like 3D) that may pop up could justify one over the other.