The National Aquarium in Baltimore is a must see if you are coming to town. Baltimore has been the home of the national aquarium for more than 20 years. The design of the aquarium is interesting and inviting. I took my son there last year when he was 9. We spent hours there and he was interested enough to read every sign at every exhibit.
They will let you know when the dolphin shows are when you arrive. It is up to you to decide whether you want to see the exhibits first or go to the dolphin show first. I must admit, I have never been to Sea World or anything, so I don't know how the dolphin show in Baltimore compares to others, but it looks to me like everyone is having a good time. I really like the way the auarium is laid out. You walk up in a spiral, stopping at informative exhibits along the way.
You get a whole new experience on the way down. It is as if you are going under the sea in a cage because you are surrounded on all sides by the glass walls of the aquarium. The big fish, the various sharks, are swimming right by. Sometimes you can see the workers in their wetsuits feeding the fish. There is a children's area where the kids can actually touch some of the exhibits and then there is an Australia exhibit which was not quite open when I was last there.
The aquarium was a vital part of the revitalization of the inner harbor area. It has been expanded several times and there have been many other attractions added nearby such as the ESPN Zone and the Hard Rock Cafe.