I sell on RedBubble, and the print quality is superb. There is less of a feeling of community, and it still is very much a popularity contest in a lot of ways, but there are fewer angst ridden teens and children and discussions are politer on the whole. I see very little in terms of good critiques, though.
I'm been on RedBubble for a few years, but I haven't had any sales. Then again, I don't put nearly as much effort into my RB as I put into my dA. I just really like the dA community a lot more.
I joined Redbubble a while ago but never sold a single item (ok, I'm still learning but I have some nice shots and they WERE accepted at large size!) I found that I had fallen in a crowd that were treating RB like facebook, lots of family photos etc...I didn't think that was allowed on RB but there you go! So...I changed my account name and started again but the layout has changed and I find it all very messy...still no sign of sales either...I'm not holding my breath!