The Dolphin Swim experience is only 30 minutes...that's not much time for the extra $110 I paid to experience it. Yes, all of your food, drinks, snacks, equipment rentals, souvenir snorkel, unlimited admission to SeaWorld/Aquatica etc. is all included, but I found the Discovery Cove experience as a whole to be higher than I'd be willing to pay again. The SeaTrek is an extra $59, and I think you're crazy not to add that in if you're spending the day at DC. If you're looking to do Busch Gardens, that's only $25 additional.
The park is a wonderfully unique experience...but it's not cheap. There are better Dolphin Swim experiences out there that offer more time/better experiences for less money. I'm glad I did it...but I'll never do it again. I found myself forcing myself to slow down, take it easy and just relax, or I would have been bored out of my mind!