Rather than me starting my own thread, allow me to piggyback...
I have never been to either one, but we have one day set aside just for a water park during our visit next week. Right now we are planning on doing BB. The reasons are pretty subjective. I think the theme sounds unique, but the main reason is TeamBoat Springs. My son saw just a short clip of it on one of the Disney travel planning DVD's and it's all he talked about for the rest of the evening.
Are there any good reasons we should switch our plans and go to TL instead? It will be me, DW, DS 4.5, DD 7 mo. & my sister. Me & my sister will be the only ones who would take advantage of the big slides, so I guess it boils down to which one is more suitable for a 4.5 year old boy who loves to swim? We are planning the whole trip around him, why should the water park be any different?