I haven't had much time to actually play with it. I really had to do a reinstall anyhow, as my system has been seriously chugging as of late.
My immediate impressions are as follows:
1. Amazing performance: I've been using systems with TI4200 and Parhelia for the last year now, and the performance increase is clearly noticeable.
2. Filtering: The 9800 has amazing IQ, as it relates to A.F. I don't think there's any question on this point, IMHO.
3. Antialiasing: Wow. It's so head-and-shoulders above anything from nVidia, it's not even a contest.
I have been playing games @ 1600x1200, 16x AF, and 4xAA...Those are some amazing settings in which to play games. I didn't try so in UT2003, rather going with a more conservative 12x10.
The bottom line is that (to me) regardless of what nVidia does with NV35, I have virtually no hope that it's going to be able to go toe-to-toe with the 9800/9700 in terms of IQ.