This was the only company that offered a 3pm snorkeling tour in that neighborhood, which I as a late sleeper really appreciated. Additionally, they were the only ones offering a tour when the rest of their competitors canceled all the tours for the day (including the Pennekamp State Park), which worked out great for us since we had limited time on the keys and the weather was bad all week.
Having said that, the visibility wasn't the best that day (because of the weather), but we still got to see a lot of fish and conch, and enjoyed ourselves enormously. The captain took us to Grecian Rocks reef because that was the only place more or less storm-free, and it was nice :) you do have to be a good swimmer on days like this though.
What I also liked about them is that they required wearing life jackets. I snorkeled in Hawaii before, where they didn't provide the jackets, and gotta admit it's so much easier to just relax and watch fish if you don't worry about floating.