I have been many times and find the Island House to just be one big classless orgy. I always stay at Alexander's Guest House. It is basically across the street sorta, from Island House. Room 15 is my favourite. But I also like Room. Excellent pool-view rooms and a nice place to hang out with new friends. It is classy guesthouse and they keep it immaculate. I have met people there 10 years ago that I still am friends with today. The have the nightly free cocktails by the pool under the gazebo and the breakfast in the morning is really really nice with quality food. The entire property is clothing optional, however I've never seen anyone just plain butt-naked except on the 3rd level sundeck.
I highly recommend Alexanders and not the Island House. The website is www.alexghouse.com