Well, AMD uses a fixed cycle - one release a month. They also have a fixed development cycle that takes roughly 3 month (all explained on phoronix a long time ago). So supporting the latest kernels is not easy or even possible.
They also only support a few distros. If you insist on using a non-supported kernel, you are on your own. That said - Nvidia might be 'better' when it comes to binary drivers, but they suck when it comes to open source drivers. AMD is working on free drivers for all cards - that is something you have to recognize. My next card will be AMD again. Supporting open source friendly corporations is simply a good thing. Besides - if you use the ebuild, even 2.6.30 works. Yes, dmesg is spammed with ugly messages. But who cares? Do you really monitor dmesg non stop?
