I went on the morning cruise with my sister and dad (sis and I are both in our 30s, dad is 64). We had initially planned on just snorkeling, but at the last minute decided to upgrade and try SNUBA. Couldn't be happier with that decision. Rebecca was a fantastic instructor and made everything very easy. I had previous SCUBA experience but my family did not, and it didn't matter at all. Instead of snorkeling at the surface and being restricted to the shallowest parts of the reef, we were able to go 15-20 feet down and essentially get a private tour of reef areas that snorkelers couldn't reach. Rebecca took pictures of us throughout the dive and was up-front about the fact that the company would charge us 40 bucks to take the pics home afterwards. We did end up buying them, since this was a pretty unique family experience.
The cruise itself is a blast, even if you don't do SNUBA. The crew is great, the food is good (try the pickles!), and the big boat makes a comfortable home base for the trip. Highly recommend it.