Both are good for familes. We like BB better for younger children 18 months to 3 years. The kiddy section is just more young children friendly. Lots of little slides the kids can go down themselves and jumping water, but not the kind that splashes an unexpecting child right in the face and turns them off. Lazy river is good at both. TF wave pool is rather intense, while BB is better for younger kids too. There is an overflow section of the wave pool near the kiddy section, and that is fun for younger kids too.
So it depends on what your kid likes. Are they adventerus? Do they mind getting splashed the face? TL has a big kiddy section, with a lot to do, but better for kids ages 4 to 7.
You can't go wrong at either. DD liked both when she was 2 1/2 and we took her back to BB when she was almost 3. For us BB works better, with a 4 year old TL might be good too.
Have fun!