This is very much a personal/family preference question. You and your kids are unlikely to be bored at either one. They both have things that are unique and fun.
Our family seemed to prefer Typhoon Lagoon, BUT--if your kids haven't ridden a ski lift or something like it--you have to go to BB and ride the ski lift at least one time (assuming tall enough kids).
Our kids were 4, 6, and 8 when we went in Sept last year. As I mentioned, we seemed to prefer TL. The kids had lots of fun in the kid areas, but also on the bigger-people tube slides.
As far as I'm concerned wave pools in general can be pretty rough when you are small (or when you are big and trying to be in shallow water with a small person). We mostly avoided the wave pools...
Well, anyway, you almost have to try both and figure out the answer on "best one" by yourself. They both have lots of fun things to do and great theming. Each person is going to have different reasons why they think one is better than the other--and they may not even be able to really say why... At this point, I can't tell you exactly why we liked TL better... I think part of it may be the lushness (green and shade everywhere). I think BB seemed a little more sunny/stark/bright (of course, with the theming being SNOW, it's going to be brighter...). I'm pretty sure both parks have a kid area with sand to play in, etc...
One more note: we found the water parks to be a great place to slow down and really enjoy ourselves. At the big parks, it was go-go-go from morning until crashing at night. The water parks were a great place to slow down, play in the sand, etc.. So, if you are there for a pretty long time (we had 12 days), I highly recommend a water park visit 4 or 5 days into your vacation.