Let me be the first to say welcome.
There have been many threads comparing the two water parks. I'd do a search and you shouldn't have any problem finding a number of threads.
Personally we don't think you can go wrong at either park, but we prefer BB. With younger children the wave pool at TL can bounce you around pretty good, even if you stay in the more shallow areas. BB's family raft ride is definitely a ton better, and there are quite of few age appropriate areas for the younger ones.
Hope this helps.