Sonny, the BOND was something I did for a very short time, because I tend to be claustrophobic, and being in the helmet in the water was too much for me. My husband, however, did the whole ride and loved it. You go under water with a few other people and a guide. You steer the BOND, which doesn't go very fast. Air is continually pumped up into the helmet. Everyone seemed to like the experience!
I did some regular snorkeling when I gave up on the BOND, and that was beautiful.
We loved the kayaking. We were in a two person kayak, although one person boats were being used as well. The guide led us through the banyan trees, pointing out all kinds of fish and other sea creatures, as well as things on land. At one point, she brought up a conch from the water and told us all about conches.
The museums and trolley tour were both enjoyable too. We did the Mel Fisher museum and saw lots of treasures brought up from the Atocha, as well as other ships. And just walking around town is a lot of fun. Next time, we'll do a walking tour of writers' haunts and bars...