Well, I've quite given up on DX10. I get 40+fps in some areas, less than 10 in others. DX9 doesn't look as good, but with almost max settings, I get a constant 30+fps no matter what zone I'm in. I'll check in with DX10 periodically, especially after patches, but until its framerate rivals that of DX9, I'll be gaming with the latter.
I am most curious to see the upcoming December patch for the game. If you heeded the HG: L's forum boards, you'd think the second apocolypse was nigh. Yes, FFS bumbled the release of the game just about as badly as a company can. But I'm still withholding judgement for the big content push in December. My gut feeling is they have something up their sleeves. If they don't, the game might be done before it hardly started.