I've been testing AH2 on three different computers all with ATI Radeons. One thing in common is that the quality settings have little or no effect on frame rate except on the 9600 XT and Pro at 1600 x 1200 AA x6 AF x16. The 9600 's see a drastic reduction where it makes no difference on a 9800 Pro. That seems strange. At 1024 x 768 and 1280 x 1024 it doesn't matter whether AA & AF are off, on, max quality, max performance or how high they're set, same frame rate. This has not been the case with any other game I've tried and is not the case with AH1. Frame rate usually take a hit when you turn on AA and AF. It's almost like they're turned on already, by application preference, which could explain the low frame rates on all Radeon cards. I haven't done a comparison of image quality to explore this possibility. Surely it's been checked by HTC already.
Edit:
Woops, checked my results and find 9800 Pro also takes a big hit when AF is set to x16 at 1600 x 1200. AA makes no difference. It turns out all three cards max out their 128MB memory at AF x16 at that resolution. At least the 9800 Pro maintains 48 fps the 9600 cards fall below 20 fps.
