We've been to Busch Gardens 3 times and still love it. In my opinion, it is more of a thrill seeker park than AK. My husband isn't one for the Disney parks - the music, the characters, the crowds make him crazy. He could never step foot in a Disney Park again and be a happy man. However, I love Disney and he goes to make me happy (what a man

). He does however, like some of the Animal Kingdom. Well, he likes the Roller Coaster and the Safari...maybe the Animal walks, but that pretty much sums up our time in the AK. We can do the AK in 2 hours.
When we go to BG, well, thats a different story. They have the craziest roller coasters. They have beautiful animals (their white tigers are BEAUTIFUL!). They have these tours that are so memorable that you just brag about them to your friends. We got up close and personal with a baby giraffe and got to feed him and his mama. We were literally less than a metre away from a black rhino with only a culvert separating us. They don't have this anymore since its no longer owned by Anheiser Busch, but they used to have free beer tasting. The clydesdales are a sight. We don't find the lines that bad - in fact, we can ride multiple times at many of the roller coasters. We can stay there the entire day and not be bored at all. Price comparison is obvious....BG is cheaper in the park admission, the food in the parks, the tours, etc, etc.
But, do your homework with BG. Call them before you go. The last time we went we were there for Grade 10 science day (what the heck riding roller coasters over and over has ANYTHING to do with science is beyond me, especially since I didn't see any kid writing ANYTHING down). Literally, when we pulled into the parking lot, there were at least 30+ yellow school buses parked there. We were NOT impressed that Busch Gardens didn't have anything on their website. We were told that they do these often with the surrounding communities. It was SO busy that day and the kids were not supervised appropriately. They were cutting in line and my husband lost it by the end of the day. He can be intimidating, and I think he scared some kids who tried to cut in line. That day was not a good day at BG, but we are planning on going back again this year because my step son will love (he hasn't been yet).
The shuttle still operates from Sea World and it is awesome. If you are planning on getting a combo ticket, this is the way to go.