If you have never been to Disney World, or haven’t been for 20 years, then go ahead and spend a day or two at Animal Kingdom. Check the schedule for the shows — bird show, etc – as these are as good as or better then the “rides”. You will either be staying in the Animal Kingdom Lodge ($200+ per night & up) or you don’t mind paying for a full day of Disney, but this means you’ll leave after a few hours when the babies get tired and cranky. That is the ONLY reason I’d urge you to choose Disney: if you have been to Disney before, or will be able to bring your children to Florida again when they are older (like 8 & 10), then let Disney wait.
Busch Gardens will be less exhausting for younger children and will save you tons of money as well. Not only is BG admission cheaper, but prices for food and gift items are wonderfully lower than at WDW. There are hotels in easy walking distance to the park (there are auxillary pedestrian entrances as well as the main entrance), but some of these hotels are surely not the Marriot… however the prices are very reasonalbe and the convenience can’t be beat.
The park itself is a lot like a large modern zoo, the kind where animals have big islands to roam on instead of being confined to little cages. Of course, there are roller coasters and other rides among these exhibits. There is a ‘kiddie land’ with nothing but rides for the very young, but there are also carosels, bumper cars, sky rides, and so on scattered throughout the park. Just as at Disney, get a schedule of shows, especially the animal shows.
So, BG is a better choice for the children, who are really too young to appreciate Disney OR to handle a full day of “The Disney Experience”.
Exception: if for the adults this is a rare opportunity to do WDW, go for it; there is nothing else like it, and you should do it once in your lifetime. Another exception: if you have the money to stay WDW hotel right next to the park (so everybody can nap), or if don’t mind leaving Disney after a few hours, give your kids the treat.
If you are one adult and two small children, you are going to have problems getting the group onto some rides. Think about it. Two to a seat. Are you going to let them go by themselves? Some rides don’t allow children that young to ride by themselves. You can’t go with them one at a time; who will watch the waiting child? So you might want another adult, even if you have to hire a guide or nanny for the day. This applies to BG and WDW both.