Unfortunately the ATI/nVidia debate is anything but clear cut. Here's my opinions on the subject:
1. ATI's cards have significantly better image quality (I say that based on many experiences with both brands of cards recently). This goes for both 2D (where it is greatest) and 3D. ATI's antialiasing also works MUCH better than nVidia's.
2. ATI's recent cards are generally overall slightly better performers than nVidia's cards with comparible price points. AH2, however, currently does not run well on ATI 9500 and up cards though. My Ti4200 performs better in AH2 than my Radeon 9800 does. Considering that no other game I know of benchmarks results for, or have played on my machine, are the same I'm fairly certain this is a software issue with either ATIs drivers or AH2 itself. I'm really hoping HT can find the reason before AH2 goes final.
3. nVidia's drivers are still FAR superior to ATIs drivers. It pains me to say that, but so far every new ATI driver version I've used (3.7s, 3.8s, 3.10s, 4.1s) all seem to break one game while they fix another. To make matters worse, newer drivers sometimes reintroduce a bug that was fixed in a previous release or sometimes cause performance in one game to plummet. At least there doesn't seem to be any major 2D application issues in ATIs drivers, as in the past where my experience with ATIs drivers were in a word - terrible. (One Rage 128 driver version I tried about 3 years ago corrupted one of my Win2k machines to the point where a reinstall was necessary as it wouldn't even boot in safe mode.) With nVidia's drivers, there's a good chance that installing a new game even with older drivers will not result in the game having too many issues to play. With ATIs drivers, I can't say the same thing. It seems like it takes at least 2 driver revisions to get rid of most of the bugs in any new game. To ATI's credit, they have been releasing new drivers every month, so at least they are making an effort to address driver issues on a regular basis. Unfortunately, I don't exactly like to be updating video drivers on a monthly basis without knowing for sure that the new set won't break something that worked in the previous version. (I was joking with someone recently that ATI needs a "select video driver" prompt at bootup with the past 5 releases available... )
All is not perfect with nVidia though, as their more recent drivers (40 and 50 series) are not nearly as good as the 30 series drivers were. nVidia also seems to be sacrificing image quality for performance in an attempt to draw closer to ATI recently as well. I can definately say that the IQ with my TI4200 card is notibly better with the 30.82 drivers than with the newer 40 and 50 series sets. They also haven't been matching ATI in how quickly they resolve reported driver issues recently either.
So, basically what you are left with is: ATI - superior hardware, nVidia - superior software. Take your pick...
