Stay on the EAST side of the island where all the large resorts are. The west side where all the cruise ships come in is very junky. Its worth visiting, but be prepared to feel like you are in a third world country. Also, be prepared to have the locals attack you to come into their stores to shop. We got very tired of that. If you stay on the east side, you'll be happier. Snorkel Palancar reef. Very nice. If you want to take an excursion head to Xel-ha(eco-park with snorkeling) and Tulum(mayan ruins) on the mainland. It was a very enjoyable experience, but be prepared to be gone a whole day.