Now, i've never heard of powercolor so I'm a bit biased to the XFX... but does it make a difference which I go with. Clearly the powercolor one is cheaper, but is it worth spending the extra for the XFX brand?
Powercolor, if you are trying to save money. XFX is you are going to overclock... which you shouldnt really need to overclock a beastly card. No need to for the games available... Unless you wanna be overly retarded and run WoW windowed and Bioshock windowed while watching a movie.... you get the point.
Both cards are the same except one is branded as XFX the other Powercolor. You are paying for the support by each company. XFX does have good support and is a lifetime warranty, (1 year if you don't register the product on their site, I believe). However, personally I never keep a video card beyond 2 years so that warranty isn't a concern for me. The Powercolor has a higher clock, which would be a benefit.
XFX has good support and a following in the gaming community so they will have alot of loyal "fans". But buying a powercolor will not give you an inferior product in any way.