Personal experience? I love it. I have not had an issue with it. Most people I know have been able to bump that card up to 690, with the memory clocks left alone. That is a major increase over the GTX series.
I know a lot of GTX cards can get bumped up, but I have yet to see any umped that high. If you are into vmods you can probably get a bit more out of it, but that card already screams. I would suggest grabbing a PCI slot cooler ( you can see the one in my pics) that draws a little more hot air out of there.
I have not exceeded 81c on this card yet, which is pretty damn good w/ the clocks it's running at. I usually idle @60c. No artifacting or any other troubles as of yet!
I have found that 80% of people that bitch about bad cards usually don't have a clue what they are doing.... Lol one guy returned his because "every time I turned on the fricking computer the screen was blank & the card screamed like a banshee...damn POS! I returned it and just decided to get a pre built machine!" ...too damn bad he never bothered to connect the power cables to the GPU (which was why it was screaming at him)
...Here is a good place to submit benchmarks. You can see I've got 2 records, one in 06' and one in SuperPihttp://forums.guru3d.com/forumdisplay.php?f=32