HH in August is usually PACKED! We have been going to HH since they open with the exception of 98 & 03. We used to be able to go over the Labor day week and it was great, very quiet compaired to mid August as most kids had to be back at school by then. It can be a long wait to get seated at a resturant so go early and be prepaired to wait.
No matter when we went, the beach was still large enough to spread out and enjoy without feeling like you were the 6th man in a 4 person hot tub.