I'll take what I've seen with my own eyes (I have every Radeon card from the 9800 Pro down to the VE and every GF card from the GF 256 to the 5900 Ultra). I've done my tests, I've done my benchs, I've played my games, and the end result is what's sitting in my P4HT 3GHz 800MHz FSB (Hint: 450/800 stock).
I'm sorry, folks, especially the ones that managed to drudge up two links where ATi beat out the FX in every test. $10 says those sites are ATi biased. Whoever said the 5900 Ultra falls dramatically behind when AA comes into play is full of crap, and needs to start reading more reputable sites. Does it lose to the 9800 Pro? Yes, it does, by 2-3 fps in the common benchmarks.
Also, 52db cooling? Do you HAVE a 5900 Ultra? The cooling is nothing like the 5800 Ultra, and you don't hear the fan whatsoever, so please, get your facts straight.
Also, announcing a card and releasing a card is two different things. ATi doesn't even have production cards yet. How do I know? I don't have one. nVidia will be releasing the NV40 around Christmas time, and I imagine the 9900 will come out around the same time.
BTW, I do Compatibility testing for the company I work for, and this includes benchmarks, driver testing, and various other things, so I do know what I'm talking about. I talk to ATi and nVidia on a weekly basis, and keep informed on exactly what's going on. Why am I telling you this? To validate my "claims". Want actual proof? Ask for it, and I'll be happy to run whatever tests you wish on whatever computer you wish (I have pretty much anything from that P4HT to a PPro 200, including a 3200+ Barton, 2800+ Barton, etc etc)