We had lunch there on our last visit. It was peak lunch time, and although the line to order was lengthy (it did move quite fast once we took the plunge and hopped in), and the downstairs areas were jam-packed with people, the upstairs seating area was only half-full, and relatively cool and quiet. I had a lobster roll, which I loved. We're not from New England, so lobster of any kind is a rare treat for me, and this roll had a generous amount of not-overcooked lobster in it, and was nicely toasted. I also had a lemonade slushy (refreshing, but tasted like fake lemon flavoring rather than actual lemon - I'd get something different next time) and a tasty blueberry cobbler for dessert.
All in all, it was one of the best counter-service meals we've had at WDW, in terms of quality and value, and the upstairs seating is almost a well-kept secret.