You'll get a million different answers and I think you won't know until you try them both. Before my first family trip in 2006, I was positive (based on what I'd read on the boards) that we'd like TL better. However, we all much preferred BB. The good news is that both of them are awesome. The only attraction I'd avoid is the family raft ride at TL if the wait is longer than 10 minutes. It's a pretty lame ride and it typically has long waits, plus you have to carry your own huge raft up the hill.
At TL, we love the water coasters (Crush n Gusher) and snorkeling with the sharks (wear a life vest even if you're a great swimmer so that you can slowly float along the top, and make sure you rinse out the mask before you put it on. They use harsh chemicals to clean them.). The tropical theme is very nice at TL. We were not huge fans of the wave pool.
At BB, we LOVE the family raft ride (Teamboat Springs, maybe? It's a super fun, really long ride), and Downhill Double Dipper. When my kids were between the ages of 5 - 10, they adored the Ski Patrol Training Camp. If you have kids in that age range, I'd choose BB because the family raft ride and Ski Patrol area are so awesome!
Both have nice lazy rivers and yummy mini donuts! Enjoy! We love the WP's and go at least 2x every trip. Oh, and my daughter loves the steep body slides at both parks but the rest of us avoid them! Once was enough for me!