They just opened a store a few blocks from me but I haven't been in yet. It's basically on my walk to the subway so I'll check it out and report back. What I've seen in trendy consignment stores has been pretty good quality, though it's often synthetics that I happen to like less than pure cotton.
I like some of their stuff, and their ethic as you mention. Overall it's one of the stores that makes me realize I'm a different generation than the current trendsetters -- sometimes I just sort of don't get it, which is unusual for me. (But I just looked at their website and I like the most recent arrivals, so maybe there was just one season that didn't resonate with me?) Anyway, I keep meaning to go in their store. I'll report back!