We had a very good experience at Hayman this summer. We were quickly upgraded to the Italian Penthouse after reservations acknowledged making some mistakes on our booking. The Penthouse itself was beautiful, clean and had an amazing view of the water.
The resort's restaurants, while expensive, were generally very good, with the Oriental being a real stand-out. We also enjoyed the Beach Pavilion, which has a nice tropical feel, for cocktails and tapas.
The adventure highlight for us was the helicopter flight to a nearly deserted Whitsunday Beach, and to a dive platform on the Reef for snorkeling. Hiking on the Island is also fun, with great vistas everywhere. In the evenings, we played board games and read in the Library, or watched movies in the theatre.
Overall, while pricey, the experience was worth it, and we would go back.