Definatly Blizzard Beach.
We found TL a NIGHTMARE with our toddler. The wave pool is too intense and it knocks the kiddies over, even right at the edge. The kids area is confusing and its sooooo easy to lose sight of them. In fact the whole park is very "samey" in its theming and quite disorientating. Very easy for little ones to only move a couple of paces and be completely hidden from sight....not great with all that water about.
My DD got badly scraped on the slides at TL as well, plus their were snakes in the lazy river (lots of foliage hanging down).
DEFINATELY, 100% BB...its more open and easier to keep and eye on little ones here. Oh, and dont get me wrong TL is a GREAT park, but much more suitable for older kids and adults. If you have pre schoolers that are confident swimmers, then TL may also be fine, but ours are both nervous around water and hated it.