For me it was a mix of things. I've owned plenty of cards from both companies... I know it's mostly my luck, but just about every Nvidia card I've owned has bellied up or gave me problems that I could not stand... For this build, I actually originally purchased a 4GB GTX 680 and waterblock for it but didn't even take it out of the shrink-wrap before I sold it and got the 7970 (and put some money back in my pocket to boot). For some reason the thought of building another system using nvidia in it gave me a bad taste in my mouth. There is a high probability that it would have been fine, but it just made me feel uncomfortable... Plus the damn thing was expensive. Performance per dollar is important to people like myself who don't have excess amounts of cash floating around.
With the ATi(AMD) side of things, the cards have always functioned flawlessly. I've never had one ATi/AMD card go bad. I've also had better overclocking luck with ATi/AMD. I'm not saying that they don't have their problems (occasional driver/game related issue), but nothing that prevents the card from working. I've had driver and game related issues on the nvidia side of the fence, too... but only with my crap luck, have I had cards go completely bad (like GPU fried or similar) on my Nvidia cards. This is not the norm, but it's my experience and it makes me hesitant. Plus, my last nvidia card I had for any decent length of time, the 9800 GTX was plagued with driver crashes, despite having no hardware issues. It just seemed that 8 out of 10 drivers I used with that card would crash even at desktop... It was enough to make me want to throw the computer out the window. To sum it up, the ATi/AMD cards I've owned tended to "stay" in the system longer than when I owned Nvidias... They would stay until I wanted to upgrade, as opposed to when they died out and were absolutely un-usable (with the exception of the 9800 GTX which was all driver-related).
3DFX VooDoo 3 (Used till I wanted upgrade) (Irrelevant as 3DFX is gone)
Nvidia TNT2 (Used periodically, but often switching back to VooDoo3 till both were replaced - c'mon, back then 3DFX's glide was THE api to use for many games)
Nvidia GeForce 2 GTS (Used till crapped out due to un-known reasons, though I will admit it was awesome until that point)
Nvidia GeForce 4 (Very short life-time, it cooked itself... GPU dead - good thing I saved up a bunch of money to waste on that one...)
ATi 9500 Pro (Used extensively, modded, overclocked, etc till I upgraded - sold card after upgrade)
ATi 9800 Pro (My longest living video card - this lasted me longer than it should have. Overclocked. Gave to ex-girlfriend after I was done with it where it lived out the rest of it's days till she built a new system)
Nvidia 9800 GTX (Great card at stock when drivers didn't crash non-stop... wasted money on a water-block on it as over-clocks were completely unstable on it. Constant driver problems at stock, why would OC be any different? Sold card after upgrade)
AMD 5870 (and xfire) (After coming from the 9800GTX, this was a breath of fresh air... Powerful card, ran everything I threw at it with great performance and overclocked like a champ till I added a second one in crossfire (also overclocked just as good) which I used as what I would consider my best set-up ever till I did my new build with the 7970 - sold both after upgrade)
AMD 7970 (again, super powerful card, runs everything I throw at it well)
I'm in no way a fan-boy, I just feel like I've been burnt by nvidias products in the past and I have bad luck with them. I'm sure I'll own nvidia again some-day, but I've been enjoying AMD and they've been good with me so far. Due to this, when I do builds for non-gamers or casual gamers, I also always use ATi/AMD cards as I've never had one go bad... I only put nvidias in a system for someone if they specify that they want it... besides they usually cost more. I've had friends unfortunately have their nvidia cards burn themselves out as well. I don't know what the deal is, but I chock it up to crap luck.
We need both companies to exist though, heck I wish there were even more choices in the marketplace like their used to. Heck, we used to have Nvidia, ATi, Matrox, 3DFX, PowerVR, and more...
I say choose what works best for you, get the best card you can get for the money you can afford. Both companies offer great products with different features/values.
Edited by TamaDrumz76 - 5/14/13 at 5:47pm