I always go to Frank's.
It seems like everyone has their own favorite fruit stand in the Market... well, I ALWAYS go to Frank's Quality Produce. I'm friendly with the staff and they always give me great recommendations of fruit I've never tried... without them I would have never known about the delights of persimmons and strange-looking summer melons. Everything is always ripe (or, if I tell them I'm going to eat it in a few days, they give me one that will be ripe then) and very high quality. You won't be disappointed if you shop here.