I haven't been to the SunDiver yet, but I am getting married there in Sept. I have heard nothing but good things about the food, the cleanliness of the rooms, the staff, and the beach. They have been extremely friendly, helpful, and accommodating through all stages of the wedding planning. It came recommended to me by the wedding coordinator on the island, and she works with all the hotels and isn't paid by the hotels to recommend them (I don't think), so it seems to be a pretty unbiased recommendation.
You should do a search on the board for SunDiver. As it is small and on the north end of the island, there isn't a whole lot of info, but what's there is very positive. Best of luck to you!