I was there two years ago in March and it was great. It was my first cruise and Playa Sol was my favorite beach on the entire cruise. Head down to Carlos 'n Charlies and Senor Frogs before you get back on the ship. A lot of fun!
I've been there twice, once when it was brand new, and once last year. A very nice beach, better than anyone's private island. Get there early, do you shopping in town or drinking later. The beach is great and there's also a pool, and you can get floats, and assorted other things including Jet skis to rent. There's a nice restaurant too, and you can get all kinds of drinks from the bar, including a swim up bar. Also, there's an area where they have all sorts of stall for native goods, silver jewelry, onyx, etc. Its one of my favorite places to go after 12 cruises.