gotensan01 is right, both PNY and XFX received some criticisms, my friends had good experience with XFX, bad experiene with BFG and eVGA, but havn't tried PNY. I'm not sure whether it's a model-specific thing wiht the bad experience though.
There IS a difference between PNY and XFX though, the memory of PNY run at 900MHz, while that of XFX run at 1GHz - that's one of the reasons my friend bought XFX and think he got a good deal (at early Dec there isn't another brand offering this product, and later after they ship, most run at 900MHz). So far, after 6 weeks intense gaming, the card still runs great.