Go with Captain Marvins....
We did on our June 22 Western cruise. We did the Coral Gardens, Barrier Reef and Stingray City tour. We had a great time, they did a nice job and they were friendly and helpful. We saved a few $$ over the Disney Excursion too!
Try to book early in the day to allow yourselves extra time to shop or to enjoy 7 Mile Beach. We asked the Captain Marvin's shuttle driver to drop us at 7 Mile Beach on the way back to the office. They did without a problem (at the Holiday Inn) and we spent a few hours there. Then we took a taxi ($4 each) back to the ship.
Enjoy!!!
Howard