After I got my Dell U2711, I decided I needed a new graphics card, so went for one of these. In BF3 on high settings I get around 50 fps, at 2500 x 1400 res.
-Noise levels; Excellent, but then again I have four case fans so YMMV. I was wary after hearing reports on the internet of whiney fans on the reference 670's but this one is more than fine.
Overlocking; with this particular card, I would say not that great tbh. Could be that it's because this is a reference model, who knows. Either way, I'd rather keep it at stock, and prolong the life of the card, than gain say 5 fps from overlocking it.
I've ordered a second one to try and improve my fps at this res. I've heard the scaling is very good, and micro stuttering isn't as bad as it used to be. Depending on what NVIDIA bring out end of this year/start of next year, I might be tempted to change cards. Only of course if they bring out a single card that is as powerful as two 670's though, although I can't see that happening.
Evga RMA is great too. I've dealt with them in the past, nothing to fear :)