Then cheapest would be best. They're both good cards for gaming.
The 7950 would be more productive in some applications and software suites. If for some reason you required CUDA, I would point you to a different Nvidia card. Since, the 760 has fewer CUDA cores than the 670 or 660ti.
And I don't actually know too much about this stuff. Most of what I say is common knowledge or reiterated from any number of posts in these forums. Posts that have obviously been verified. blah blah blah.
hmm the recent reviews on that card are bad, I actually was considering the MSI card till I saw those. Now I'm considering the sapphire vapor x card. Its more expensive but the cooling is top notch giving better overclocks and it also cools the memory.
If you're particuarly worried about the MSI, the HIS IceQ X2 turbo is probably the best of the AMD cards. It just happens to have a super long PCB which doesn't fit some cases.
The Sapphire vapor-x is 50:50 love hate in these forums. Some people recommend it and other's don't. I forget why... Seems to be a lot of myths surrounding the card. Bios problems. Voltage lock myth (true/untrue... I have no fuckin' idea).
Main reason for recommending the MSI is because it isn't voltage locked. You don't want a voltage locked card on a GPU series that happens to be great at overclocking. It's an annoying handicap.
What ever you do don't get the XFX 7950, I got it because it was the cheapest and I was stupid not to look at the cooling reviews, I wish i had bought the Sapphire Vapor X Card now. :/ Don't get me wrong it is still fantastic in terms of performance, just runs real hot.
I think 3GB is the sweet spot. It allows you to upgrade to higher-res panels. It'll be a good amount for some time. But the 700 cards resolved the bandwidth problems found in the 600 series. So, 2GB doesn't put anyone at a serious disadvantage. Not at this time.