Here's a little breakdown, filled with my often flawed opinions
Wave Pool:
Typhoon
Slides:
Blizzard
Kids:
Blizzard (?)
Lazy River:
Typhoon
Theme:
Typhoon
Extras:
Typhoon
Overall: Typhoon Lagoon
Wave Pool - I don't care what the ladies say, size matters. And Typhoon's wave pool is huge, and makes huge waves. Plus, it goes between the "big wave" and the "choppy waves" (scientific terms, of course). Blizzard sticks to one wave type (choppy) and is a smaller area.
Slides - Blizzard has more slides, taller slides, and faster slides. The only thing they don't have is Crush'N'Gusher (thats at Typhoon). However, if your group is looking to do a lot of sliding, Blizzard is the place to be. Love the darkened tube slide on the back of the mountain, and the family tube slide is a hoot.
Kids - I don't have kids, so I have to base this one on which kids' area looks like more fun. So I went with Blizzard with a question mark. That means I'm not positive
Lazy River - For my mom, who spends most of her day enjoying the lush vegetation of the Typhoon lazy river when we visit... this vote is for her. I just love all the plant life surrounding this river. Almost makes you feel like you're not in the park. Almost...
Theme - While I think the conceptual theme of Blizzard Beach is excellent, the fact that Typhoon has had so many years to "grow" (plant-wise) gives it the edge. It is so lush and beautiful. And has nice touches to remind you that a "powerful storm once roared 'cross the sea"... I think thats how it goes...
Extras - Hey, you can swim with sharks at Typhoon Lagoon. You can ride a chairlift at Blizzard Beach. Sharks can eat chairlifts, so my vote goes to Typhoon
Overall - If you're looking for an enjoyable overall day at the waterpark, Typhoon should be your destination. If you want slides, head to Blizzard Beach. Or win the lottery and go to both in the same day. But since I don't know your lottery-winning-status, and this is the "overall" category, my pick is
Typhoon Lagoon!
Hope this helped a little bit
ExBellhop