It's a beautiful island, there are many things to see in nature, some beaches are definitely too crowded though. It's also quite pricey but if you're patient and don't want to overpay you'll find reasonably priced restaurants and accomodation.
I'd say the best snorkeling and diving in SE Asia. Amazing viewpoints. Delicious food. A lot of various activities. Some things are a bit overpriced, but okay, it's a very touristic island after all.