It has been many years, but I had taken the Dolphins in Depth tour. The first thing to know is that this is not a swim around with the dolphins type of encounter you may find at other resort destinations. You do get to enter the water with the dolphins but stay on a shallow ledge at the top of the aquarium. They are then brought to you, where you can gently "pet" them and pose for pictures etc. They also stress that if the dolphins do not wish to participate, they will not force them to. I don't know if that has ever happened though.
The tour starts with a behind the scenes tour of the aquarium, followed by a group discussion/education on conservation and dolphins in a back stage lounge. we then "on stage" and watched a scheduled research program with the dolphins and cast members. The final part of the tour is where we put on provided "shorty" wet suits and went back stage again to the top of the aquarium for the face to face time with the dolphins. We were also given a photo of us with the dolphins as well as a "Dolphins in Depth" t-shirt as part of the tour.
While it may not have the excitement of a more hands on encounter like other resorts(which I never did) I still enjoyed it immensely and going backstage is always a treat where you get to do and see thing most guest do not. Having said that though, if you are looking for a more scenic, constantly moving, outdoor type tour then maybe the African Trek is better(which I will be doing for the first time in February).
Hope this helps!