Well, Ive only done TL, but I have seen a lot on the Travel Channel on BB.
TL has a area where you can swim with the fishes (and harmless sharks)- missed this last time, but sounds really cool.
has some fun, but short family tube rides.
has an enormous wave pool- and the waves if you swim out are typhoon-size, they run on a random timer I think.
The lazy river is fun, but the slides look better at BB.
Humunga Kowabunga wasn't as fun as I thought it would be- basically straight down and very fast- kinda hurts actually. The ski jump looking one at BB looks like more fun, HK is also in a dark tunnel.
We enjoyed TL, it was a great way to stay cool, but felt like we did everything and didn't feel like anything was really worth repeating, I mean they were fun, but not eye-poping, "Hey! lets delay lunch and do that one again!" stuff- and BB has a nearby mini golf- thats kinda cool too, right?
Id say if you loved BB, stick with it. If you want to try something new, Wet n' Wild (I know, I know, its off property) but its won awards as one of the best water parks in the country.