Due to some strange pricing anomaly, the prices for these two cards are not too different (in fact, I can get the older Sapphire 7950 OC at a lower price than the MSI 660ti PE). I've looked at all the benchmarks, and while the 7950 isn't too bad (and should be theoretically faster), nVidia optimised games like Battlefield 3 and anything using the Frostbite 2 engine have the 660 Ti out in front.
Now, the question is, how does GW2 perform with the respective cards with their latest drivers at 2560x1600? Tom's Hardware hasn't updated their article, and also drivers can play a part. My 560 Ti has shown an increase of 30% in updating to the WHQL 306.23 drivers. Given the age of testing, I'm not sure if I can draw a conclusion from the article. Any gamers who have experience either card (or better yet, both cards) care to share their experiences?