I haven't been to any of the places you listed, so I can't compare but we had a really good time snorkeling at Pinel last year. Saw a couple of turtles, an eagle ray and lots of colorful fish. Read someplace else that they have gone up on price at the snorkeling hut ON Pinel but maybe if you can find an excursion that takes you near there or Tintamarre, you might see the best that SXM has to offer??

By the way, I had to google what bareboat charter meant - I thought it meant something else