There is a good snorkeling just offshore, although the practice of dumping hundreds of paddling Chinese in life jackets into the drink to feed the fish has made some of the fish quite aggressive, which could be a shock to some people, especially kids. There are some nice anemone fish (clownfish) colonies and a surprising amount of coral. I would say the island is a good place for freedivers, but as you point out, it is lacking in good accommodations. What is a available is overpriced. Probably the best of the lot is the place back in the woods, called Paradise Lost, run by an American named Wally who is quite friendly and helpful. If you go with a Thai you can expect her/him not to be too crazy about sleeping in the forest, even in a bungalow with lots of (friendly) dogs around. Wally doesn't have a lot of bungalows so he probably gets filled up pretty quickly in season.