The brand makes a difference, perhaps the warranty and any extras they may offer, plus sometimes certain brands offer higher performance cards.
So check reviews for each card before you buy, and what people's experiences are with the brands, as well as if there are any extras being offered,
I haven't used either brand, so I don't know.
Whichever you choose, you'll be very happy with it, as long as you have a good enough PSU and a powerful enough system for it.