Highly recommend this place. It's very clean, cool and quiet. Location is great. If you're into medium-length walks, DC downtown is comfortably and safely reachable on foot. And if walking is not your thing, then public transport is abundant. The immediate neighborhood is nice and beautiful too, with lots of small shops and cafes. Also, that back alley pizza pickup is very convenient indeed ;).
Having soft drinks available was also extremely nice and helpful touch given the heat.