I haven't had any issues with my 7950. If I needed to upgrade I might go with a Nvidia, but its keeping everything on high at 60 just fine for now and I don't have any crashes (since I replaced my POS motherboard that died)
No matter how good this game is, it will be a disappointment. People are putting the hopes of the human race behind this thing. I'll be happy if it ever releases with half the promised stuff in a functional way.