We did both in June. As noted before, it's all about your preference. For better slides and rides, BB is definately the answer. For the better (much better) wave pool, it's TL. Both have nice "Lazy River" attractions, and kiddie areas. The new slides at TL are OK, but we weren't overly impressed with them.
So choices in summary are:
>>>>Rides & Slides = Blizzard Beach
>>>>Wave Pool and Laying out = Typhoon Lagoon.
For us, if we went again, it would be BB.