We had a great meal at Mariners. Sure the food is slightly overpriced but so is everything else on Hamilton Island - once you get past that you'll enjoy your meals much more. Our table of four had 2 of the daily specials and 2 items off the regular menu. Everyone really enjoyed their meals and all plates were clean when they headed back to the kitchen. The wine list is fairly thorough and has everything from $25 bottles to some pretty exclusive drops.
Service was also great - so good we figured our waitress must have been North American ;)