Everyone in our family prefers Blizzard Beach, for these reasons, but your mileage may vary:
1. Wave pool is very intense at Typhoon Lagoon. A big wave comes every 4 minutes or so, so there's no real chance for younger kids to swim, and even in the shallow end the waves are pretty strong. My kids (7 and 8 yrs) didn't enjoy that at TL.
2. Wave pool at Blizzard Beach is more of a constant gentle "bobbing" wave, and there are inflatable tubes in the pool, very fun to bounce around, and it's mild enough that my kids can swim in it.
3. I feel like there is more to do at Blizzard Beach, especially for the 6-10 yr old crowd, who are too tall for the little kid areas. The "Ski Patrol Training Camp" at BB has things just for this age group, including an iceberg challenge, some smaller slides, and a zip line that my kids couldn't get enough of. We spent more than an hour just in that area. TL doesn't have anything like this.
4. I feel like there are more slides in general at BB, and more styles of slides.
5. The family raft ride is a much longer ride at BB, and the rafts are brought up on a conveyor belt, whereas at Typhoon Lagoon you have to carry up the family raft yourself and it is HEAVY.
6. The ski lift is fun. We love the whole ski-lodge-meets-beach theme throughout the park.
JMO, but I feel like BB is just as lush as TL, and I think BB has more shaded chairs because BB has a lot of . . . I don't know how to describe them but wooden roof covers over groups of chairs, sort of like a cabana but not with cabana service - and I'm not talking about the premium paid chairs, just regular chairs with nice overhead sun protection. It also has groups of chairs tucked away in shady areas where you wouldn't expect.
That being said, if you are big thrill-seekers, the two thrill slides are currently closed at BB for extensive work and no one knows when they are opening again. However, I would imagine Disney is working on that as quickly as possible, because when we were at BB yesterday, the crowds were slim (great for us, because we don't do thrill slides and we don't like crowds). So if you really want thrill slides, you should head to TL.
Either way, you will have a GREAT TIME. Typhoon Lagoon is plenty of fun too, and for lots of people it's their favorite. BOTH parks have an ice cream treat called the Sand Pail, which is super fun to share - big plastic sand pail filled with chocolate and vanilla softserv ice creams, chocolate cookie pieces, waffle cone pieces, sprinkles, hot fudge, loads of whipped cream on top, and cherry. At BB, you'll find it at I.C. Expeditions, and at TL it's at Happy Landings.
