There are definite higher quality brands (asus, msi) and a bit lower quality (powercolor,galaxy). Most others fall in the middle, and in my experience going around and reading reviews and looking at things like warranty length and how good the company's support site is will tell you a lot.
This is all just from my personal experience, i haven't bought every brand, but from what i have had, and many hours of reading through other people's gripes about their hardware, it's what i've come to.