1st time in Caymens, we used Captain Marvins. It was great. No crowds, 2nd boat at the sand bar, didn't pay til we checked in. We did sand bar, Hell, turtles and shopping (extremely expensive). We got back to the boat just before the final tender left. We shopped for about and hour and that was enough time for me due to $$$.
This time we booked with Moby Dick as they pick you up right at the pier. We selected them as one of our party has to use walker and we didn't want to have to walk to Captain Marvins.