I posted this in another thread (on 23-Feb-10), and I think it still a valid personal comment in the ATI vs nVidia graphic card debate. Note that I am a nVidia fan, but that for my recently purchased laptop (Dell Studio 1537 - purchased 15 months ago) I deliberately purchased ATI hardware (because of concerns wrt nVidia graphic card quality) …
I think the main reason many Linux users are unhappy with ATI is their graphic drivers are either typically lagging nVidia drivers when a new Linux release comes out, or in some cases ATI drivers are simply bad (note I say some, but NOT all cases).
Case in point … it was only last week that the ATI drivers were formally updated for openSUSE-11.2 … and I am now finally going to give serious consideration to updating our family laptop from openSUSE-11.1 to 11.2. This is about 4 months after 11.2 was released, and many many more months after the 11.2 milestone cycle was in process. Many Linux users (and indeed many openSUSE users) find that “lag” from when a change is made to Linux (where it be a new kernel, new xorg, or new distribution version), to when a new ATI driver comes out, to be upsetting and for them unacceptable.
Somehow, nVidia appear to be able to put their drivers out quicker.
Another nice thing about nVidia, is they have implemented VDPAU for Linux, which is the equivalent of pure video in MS-Windows. This gives some old hardware some great capabilities with nVidia graphics (in terms of playing back High Definition Videos).
ATI have not supported an AVIVO equivalent for Linux (they have provided no documentation so that even if AVIVO is in the Linux driver (and I am not certain it is) it still can not be used). In fact, speaking of older hardware and graphic manufacturer support, ATI have dropped support for older hardware that they call “legacy hardware”. I think it fair to say that vVidia are still doing a substantially better job of supporting such “legacy hardware” than ATI. So if one is going to purchase new graphic hardware, it sends a message that one will get better longer term support from nVidia (for drivers) than one will get from ATI. ATI no longer support moderately older hardware.
Edit: … although I note ATI once they do support a distribution, do have a reasonable driver in other areas, such as “xrandr” support, where I have read nVidia are lagging.
Still, the poor quality of nVidia hardware, with the hardware failures that have “bitten” a number of people that I know, is not something to be underestimated, nor under stated, … nVidia have had SERIOUS quality problems. I know people who have been bitten and are very upset with nVidia because of the very poor quality of some of their graphic card products.
… and hence from my perspective, there are PROS and CONS on both sides of the ATI vs nVidia question, and I think users on both sides have some very good points.