It kinda depends on your budget. I think the one day package you are referring to will bring you on a boat tour around 5 different islands where you will get to snorkel at every island. My advice is not to buy the package from the hotel but from the tour agents. Another alternative is to hire a boat then bribe the boatman to bring you around the islands as they are usually paid by the agency and tips from tourist. It’s a beach so you can probably expect the usual stuff. There’s also a place to go shopping at Ao Nang and some seedy red light bars ^^