Boss Underwater Adventure: My wife and I did this excursion and had a great time. Basically ride underwater scooters using diving tanks and underwater helmets connected to the scooters. Was fun, something we wanted to try. It was a little murky and couldn't see very far (even with my glasses on), and had to stay in a group which meant you couldn't go exploring on your own. Controls were easy to operate, though steering was a little difficult at times.
Overall, it was a fun thing to do. Crew was great, water was warm, and got a lot of good underwater photos.
Did not do any excursions on this island. Only walked off the pier where we were inundated by peddlers selling the same stuff booth after booth. And, turning away people who for some reason kept trying to sell me drugs. However, there was one bright spot. Can't remember name of the store, but if you go off the pier, and go left for about a block there is a little restaurant / store where you can purchase internet (for wireless computers) for $2 an hour. Gave me a chance to touch base via email.
Shipwreck Snorkel & Pirates Party Cruise: Had a great time. Go snorkeling off shipwreck, slide down 70' long slide into the water, then a great GREAT pirate party. Just make a note to watch that rum punch, it'll knock your socks off. Heck, your socks, shirt, maybe even your hat :)
Sky Canopy & Aerial Tram: Will be honest, this was the most disappointing excursion we took. The ride to the tram was something out of Indiana Jones as our driver swung the bus around hairpin corners, and cars parked in the road. Our guide did an excellent job on the tram pointing out the different trees, plants, etc. Unfortunately there really wasn't much to see as this was off season, so few flowers to look at. For the price ($130 pp) it really wasn't worth it. If I had to do it over again, would skip this and use the money for something else.
We decided to be adventurous and go on our own at this island. Took a taxi with our friends Donna, and Barry, and went to Dickinson Beach. We saved a ton of money going here ourselves. Spent four lovely hours on a beautiful tropical beach, soaking up the sun. Note, be sure to put on lots of suntan lotion. Only problem we had were some small jelly fish came in with the tide, and gave us a couple little stings (zaps, not sure exactly what they do). Except for that, it was a wonderful place to hang out.
Sky Safari Zip Lining: This was one of my wife's favorite excursions on our trip. Even I who am afraid of heights, had a great time on this one. The harness system, spring stopping system, etc. made this excursion safe, and fun. Only problem was it was so bloody hot, that by the time we finally got done with the whole thing I just wanted a nice cold drink. Only to discover the drinks they had in the refrigerator were only luke warm. Oh well, still better than nothing! But the excursion was great zipping over trees, across a valley. Like I said, even though I'm somewhat afraid of heights, I had a great time, felt safe the whole time, well worth doing.