The Shark aquarium I found the best of the three parks. Mostly because of all the smaller exhibits in addition to the larger shark exhibit, though the actual shark tank I feel is the weakest of the three parks, with not having a shark tunnel or a rare species(lemon shark at SD or Great Hammerhead at Orl). Like the San Diego Park the penguin exhibit also has an alcid exhibit which is nice. One of the more unique things about the San Antonio park is that the Belugas are not kept in a wild arctic exhibit but in an outdoor stadium where they are cohabitated with pacific white-sided dolphins(one of the San Antonio park's specialties). And currently they have babies of both species which are a treat to watch, I do wish viewing was better though. The Orlando park has more standalone aquariums compared to san antonio and san diego. The sea lion exhibit is similar to orlando's but a bit smaller but better than san diegos. Like the Orlando park, the Orca stadium is covered so your not out in the sun, one of the things I disliked about the san diego park. So it's up to you at the end of the day. If I had to rank them I would go Orlando(especially as they now have san diego's emperor penguins), San Diego, then san antonio. The only reason I put san diego above san antonio as they have a few more rare species (pilot whale, lemon shark, walrus, adelie penguin vs pacific white-sided dolphin, Spotted-necked otter). The shark aquarium though does have some unuisual species I've not seen at other aquariums but I'm not knowledgeable about AZA fish collections to know how rare they are or not. San Antonio did just open a new exhibit for Aldabra Giant Tortoises which while not the most exciting additions, it is a new animal attraction which have been few and far between.
