Hello there -
Saw your ? out there and thought that I would send some thoughts on it. My party did the Dolphin Swim in Nassau back in '99. We haven't done the one in Cozumel but if your wondering if its worth it - here's my thoughts. I, my then son 13-yo son and 12-yo daughter and mother-in-law did the swim and our dolphins names were Jake and McGyver (as in the TV series). My oldest son was scared to go into the water but after seeing his younger sister go in - he went in. AND.... to this day he claims that this was the highlight of that trip. Worth the queasiness he endured to get to the place. Back then I had to schedule it myself as Disney was not offering it as part of the shore excursions. I'm glad they wised up as this was also a major highlight of the trip. I have a video, pictures of the dolphin kissing us and even of being pushed across the lagoon from their noses.
It was pretty expensive and if I can remember was supposed to run about $110.00 pp. But because I booked 4 I believe that my total averaged out to about $85-$90 pp. And I didn't have to pay for the ride over which was supposed to be paid for separately.
Not sure what the cost is now but if your really considering it, you have to decide if its right for you. I know that this is a lot of money (and I'm sure it's probably gone up by now) but if memories are precious to you, this was one trip that I and my kids thoroughly enjoyed and still look upon with fond memories. Plus, they still brag to their friends that they swam, touched and even kissed a dolphin! So whatever you decide, good luck and if you do do it, I hope your experience is a grand one.