Discovery Cove is great. It is the only "non-Disney" thing we have done that compares to the customer service aspect of Disney. It is an "all inclusive" day. You show up and park (included). They take a complimentary family photo as you enter. You will have a specific time for the dolphin swim--15 minutes of instruction with a trainer and then 30 minutes with the dolphins. You will be in groups of 6-8 with one dolphin. Everyone will get the "experience" photos--kissing dolphin, swimming with, etc. DD still remembers her favorite part. She was about 10, and the trainer asked her if she wanted to go really fast. She said yes, and trainer gave the dolphin a "full speed" type of command with DD hanging on to a fin. She absolutely loved it.
THe fee includes your lunch, wet suit, snorkel (which you keep), and all the time you want in the aviary (food provided for the birds), sting ray pool (food provided), coral reef, lazy river, etc. It can be a very full day. You will spend a bundle on photos on the way out, but.....oh well. Cost is about the same as the dolphin deals on the cruises, and you get a whole lot more. THey also offer a less expensive package for people who are too young or choose not to swim with the dolphins.