We did the Dolphin Swim in Cosumel instead, (Which we booked on the Web before the Holiday.)
It was much cheaper, but I would have paid double, because the experience was incredable.
As for Dolphin cove in Ocho Rios, I would advise you to get there early, as you won't want to leave the place. It is lovely, Take a walk along the forrest path and stop at ALL the animals and people along the way, They are facinating, they obviously care for the animals and are knowledgable - Which is a nice change these days. Watch out for the rubber Iguanas and grab some of the coconuts and sugarcane from the Stall. (Just follow the sound of drums).
And then there is the beach, We met a lovely local who kept bringing me Shells and Corals (Dead of course) "For de Lady".
You can also see the Dolphins playing, and when we were there they were announcing spare places on the Dolphin swim, so we had the opportunity to do the swim again. WONDERFUL
You musn't miss seeing the Nurse Sharks (Although I thought the pool was a bit small for them)
I could go on and on, we had a wonderful day there.