Some brands are almost always cheaper when it comes to video cards. Galaxy, MSI, Powercolor for example are usually the cheapest. On the other hand, EVGA cards are typically more/most expensive, but they also have a very good reputation for quality and support.
In theory, some of the higher priced cards may have better quality components in them (some may even be modified non-reference cards). For the most part, it's not a big deal what brand you go for in my experience. But you might get more OC headroom going for a more quality brand.