I've never been to TL, but we loved BB. My son had been 3 for all of 3 weeks when we were there. They had a wonderful little kids area. It was for kids 48" and under, I think. My 6 year old daughter was able to play there too. There were little water slides and a splashing pool at the bottom that only came up to DS's knees. There were lifeguards at the top of the slides and at the bottom. I felt comfortable sitting at the edge of the splashing pool so I could watch both of my kids play.
I believe both parks also have a family raft ride and a lazy river. Both were fun! For the lazy river, there are little innertubes that don't have holes in the bottom, so little bottoms don't fall through. I was on my big tube, holding onto the handle of my son's little tube as we floated along. He had his head back, eyes closed, and said, "Mommy, this is a gweat water wide."
We had only allowed about 2-1/2 to 3 hours there on our last day. We wished we could've gone back again. The kids are already talking more about going to BB on our next trip than the theme parks!