Can you link me which vendor you're getting this card from? The GTX 960 is almost always the better choice, since its the same performance tier and should be roughly the same price. It's cooler, quiter, slightly more powerful and will have better driver support, not to mention DirectX12 integration, going forward. You need to be careful with older Nvidia cards because they typically under support them, in order to showcase their latest series. This just happened with The Witcher 3 and GTX 700 cards. Newer cards also tend to have more rebates and free game promotions. If you can wait a week, Nvidia is rumored to be giving away MGSV The Phantom Pain with GTX 900 series cards.

In my opinion though, Nvidia is not worth it unless you're buying an enthusiast tier card. At every performance tier, AMD offers a cheaper card with a faster GPU and more VRAM. You should be able to find the AMD equivalents, either an R9 380 or 280X, for roughly the same price, which should generally beat the 960 in most benchmarks, let alone a 760. If you're willing to spend a little more, the R9 290 is the reigning king for price-to-performance ratios. It's a high end video card which can frequently be found for under $250 with a rebate.

You will get people who will try to scare you away about AMD's driver support but that's largely an urban legend. The only time you might have problems is with ports of AAA console games, at which point you'd likely have problems with NVIDIA anyway. If you're still hesitant about that, I still recommend you go with the 960. It's a great mid range card that should set you up for quite a while.