I took my family to Atlantis in January and loved it. Recommended it to friends and they loved it too.
What I really love is that not only are their displays really well done but the viewing panes on most of them are tall and start low to the ground. It makes it much easier for babies in strollers and people in wheelchairs to see things. In other aquariums you have to hold them up and if there are other people in front you can't see anything.
I wish it was bigger though. It's so well done ( and not cheap ) that it would have been great if they can expand it.
Absolutely one of the best public aquariums in the world. Joe Y. is one of the best and nicest curators/biologists/reefers/aquarists around.
We participated in last years NERAC, held at Atlantis and had the pleasure of dining in the large center room where the 20,000g reef tank is. Just amazing. The 'back stage' tour is also phenomenal. There are experiments and prop systems and hatcheries behind the scenes that are just as riveting as the exhibits.
Are you familiar with the Alaskan King Crab display, on the way outside to the seal show? The underwater viewing is just past the King Crab display on the right. It looks like a tunnel going down below ground level. Very cool perspective.