The Super Flower Golden Green/Golden King units are 'very good'. Others series aren't so good.
I wouldn't be comfortable recommending one of those Extreme Rock Power series units unless they got a few positive reviews.
Having said that they are probably capable of powering systems with a 5770/6850.
Exactly. I'm not planning on upgrading to anything beyond GTX 460, GTX 560. Or HD 6850, HD 6870.
So will it suffice?