TL is great for relaxing and feeling like you are in the tropics. TL has good slides, but in my opinion BB has bigger/better slides. In my opinion both are great, just depends on my mood for the day! If I'm tired from theme parks the day before I try to go to TL.
This year we arrived at both water parks when they opened (1 hour early for resort guests!!). We had the parks virtually to ourselves for the first couple of hours, no lines for slides, virtually no one there!! This was first week of April during spring break. So we rode all the slides we wanted in the morning, then did the Lazy River in the afternoon. By about 1:00 or 2:00 the parks get more crowded. I highly recommend going first thing. I thought the water might be a little cold in morning, but it wasn't. We left both parks by 2:00-3:00 when they started getting crowded.