I really like the Nvidia GTX series. They keep themselves at really good temps and they're not as long as those Radeons. Which isn't an issue for some people but I like more trim looking hardware. Other differences such as textures, aliasing and processor cores, I don't notice a huge difference between the two cards. So I would just see which one is most cost effective.
I have the asus gtx 570 and so far im very satisfied, i can play pretty much everything high/ultra settings with no problems. Of course its also what cpu you have to support the gpu you will be.
If your cpu is not stron enough to follow your card then we will have the bottleneck
That should get you better deals.
Siaynoq's Playthroughs
Hands down AMD 7870 or better.
If your cpu is not stron enough to follow your card then we will have the bottleneck