We did it in January and would not recommend it unless everyone is REALLY keen on Dolphins (2 adults, 1 6-year-old). Here is why:
A) Between waiting around in a lounge on the ship and then at port, we were waiting around for over an hour before we even got on the bus. Huge waits at port just to get everyone their bracelets - like 20-30 minutes at least.
B) You walk about 5 minutes - Then, you have about a 20-30 minute bus ride.
C) You get 45 minutes only at the Turtle Farm (the main part we enjoyed) - not enough time if your kid is actually interested in the turtles. (Though to be honest, in retrospect, I suspect DS and I could have stayed as we weren't getting in with the Dolphins.)
D) DS and I were the observers as he didn't want to go in the water with dolphins ( Extreme or other) - we ended up sitting around, with no shade, for almost 2 hours, by the time DH got changed, stashed his stuff, waited around for at least 20 minutes before he even got in the water ... then it's about another 30-45 minutes before they all get out, then more waiting for seemingly mandatory group photos, and then more waiting for getting changed again. Fortunately, I just decided to feed DS and me since we couldn't see DH anyway in the water ... so that kept the boy from being a mess. There is an air conditioned store, but that gets uninteresting pretty quickly.
E) THEN, there was more waiting for DH to find his photos on the computer and more lines to buy them.
F) After that, you get another wait for a bus ride, and then the same bus ride back.
We were wiped after that - and DS and I really only got 45 minutes of looking at turtles - with hours of waiting around.
So- it might be worth it if everyone is keen on doing the actual dolphin encounter - but it sounds like there are better places to do that.
If we had our time back, we would have found a beach for all of us, and found dolphins somewhere else.
Hope that helps! And maybe others had a much better experience, but the observers do not really have a great time. The lack of shade is mentioned in the description, I think - but we didn't know how long it was going to be.