I haven't done it although I so wanted to on our honeymoon- I even tried to book it several times, but they were all booked up (not sure when you can book them, but I know I did it at the "right" time and it was already full) I have heard it is a great experience although you don't get as much time as you think to swim with the dolphins, but it's a really great experience from everything I have read about it....Sorry I am not more help- I just know that booking it is hard to do as alot of people want to do it.
One thing- there is an age requirement I believe it is 13 years old with an adule or 18 if you don't have an adult accompanying you
It does state that Dolphin Interation is not guaranteed....