I went a few weeks ago and had a blast. Everything is available on site from jet ski, para-sail, horseback riding, pool, beach, free food and drinks. Did notice it's $5 less entree if you prepay but otherwise just go and decide day off what you want to do.
Recommend the fish pedicure. Put your feet in a fish tank for 20mins and they eat any dead skin, it tickles a bit. Afterwards get a foot massage and it's only $20.