Anyone done the Cozumel Whale Shark Excursion?

[HACKT]

We are cruising on Oasis of the Seas in June 2015 to Cozumel. Only Oasis and Allure are there long enough to do the Whale Shark excursion which takes about 11 hours, mostly travel time to Cancun, but includes swimming with the whale sharks off the Yucatan. A lot of travel for hopefully a real great time! Unfortunately there are few reviews on this trip.

SO, my question, has anyone done this excursion off either Oasis or Allure and what did you think of it? Also any recommendations would be great, like "don't get eaten" (they eat plankton). Thanks much!