Nassau is a dirty, urbanized hole. Were it not for the "straw Market" (at which my wife purchased nothing this trip), we probably wouldn't leave the ship when here.
The sail was peaceful, the snorkeling very nice, the crew was very helpful and friendly and didn't beg too much for tips, the drinks flowed freely once snorkeling ended and the water was spectacular. The only drawback was that of the 4-1/2 hour excursion, we lost 2 hours to driving. The actual "in the water" time was about 45 minutes.
I've never had a bad experience on St. Maarten. This time, we simply walked off the ship onto the beach area, rented a couple of chairs, and sat and swam and soaked up the sun for several hours. It was peaceful and beautiful and exceptionally fun!