Debating between only Aquaventure and that plus dolphin interaction, which is more than a $300 difference. Anyone with experience? Really enough time to enjoy both to get money's worth?
Usually the Atlantis excursions have transportation back to the ship about every 1/2 hour or so until 5pm, so it depends how much time you plan on spending on the water slides, etc. Also, it depends on how much you want to spend for the dolphin interaction.
There are many different levels of "interaction" with the dolphins, so read carefully and be sure it's exactly what you want before you pay for it. Some are "waist deep" in the water watching the dolphins, others are swimming with dolphins, but not all include the dorsal pull through the water, so make sure it's what you want and that everyone in your group wants to participate, or you can just pay the bystander price (where available).
I've done the dolphin interaction at Atlantis, where you're in the water with a small group of people (8-10) and you get to pet, feed, and take photos with the dolphin.
The total interaction time we each had with the dolphin was perhaps 1 or 2 minutes. It is exceptionally expensive for the amount of time you get with the animal. The kids liked it a lot. I wouldn't do it again.