One thing about dA is that their prints quality is incredible - certainly much better than anything I could get in my home town. Oh, and dA gets 20% of print profits.
True, they have good quality prints, but some artists might be depending on the profits to live and such, so sometimes the wiser choice might be to go somewhere else depending on your situation(then again, what do I know...?)
Also on an unrelated topic, how do prints works?