I gotta tell you, when we bought our APs and I added the water park option, I did it entirely for the kids. I hate being in a bathing suit in public, I hate intense sun with no shade, and I had a 3 year old that I was afraid was not big enough for a lot of the slides.
Well, after 5 or 6 visits to the water parks over the course of the year, I love them. Both of them. BUT Blizzard Beach is my favorite. I love the slow pace of the layout (winding paths, Christmas music (tropical style), and lots to look at while walking (snow men!)), the shade that is designed into the park with natural trees and structures, and most of all, I love all the things that we can do as a family. BB has the most amazing family slide that up to 5 people can ride in. It is so much fun. We hang out in the lazy river, bob in the wave pool, and hit the ski patrol training area where the kids can do the slides by themselves. We finish the day off with funnel cakes and snow cones.
Typhoon Lagoon's wave pool is intense. There is no casual bobbing because the waves are big enough to surf on at certain times. But they have surf pools off to the side of the wave pool where smaller kids can play. The family slide at TL is shorter and holds less people at one time. There was also a longer line when I went (who knows if that is normal). The little kids (less than 3) area is bigger at TL, but my 3 year old is adventurous and wanted to be on the bigger slides with her older sister.