Post the clock speeds. (Core / Shader / Mem) One could be super clocked (SC) or super super clocked (SSC) which would cause a price difference. Besides the clock speeds - EVGA has a lifetime warranty and offers a 90 "step up" program that will let you change your card to another card of greater value.
If I was you I would go for either XFX/EVGA...Atleast they offer life time warranties (like BFG, but bfg has no special programs)
With EVGA you get the 3 month step up program and lifetime warranty.
With XFX you get a double lifetime warranty. If you sell the product, the buyer gets the warranty also. They also have a very open mod/overclock warranty as well.
Paying for any other brand that doesn't offer a lifetime warranty is really pointless, MSI, asus, leadtek, etc....Why pay for something that has a 1 year warranty when you can get one that has a lifetime?