We've done two summers now at the Hilton Head Island Hilton Resort and are booked to go back this summer. For me, I choose to go back more for Hilton Head than the hotel, but its a fine hotel. Rooms are nice sized, though not true suites. No Diamond treatment in my experience, which is frustrating. But there is a very basic free breakfast (for Gold/Diamond) and they don't charge for the kids. The hotel grounds are quite nice.

This is the first I've read about the Ocean City Hilton Suites; sort of wish we were trying that one out this summer now, based on the ages of our kids (2 & 5) and the full suite set-up. Though the tranquility of Hilton Head is ultimately more appealing to me.

Plus Hilton Head allows for easy pre-/post-trip excursions to Charleston and/or Savannah if you're driving (or fly into Savannah, out of Charleston and do a one-way rental, which we did one time).