Hi Momoftwins! We love Blizzard Beach. Actually, we like Typhoon Lagoon, too, but the kids fave is BB. Both parks have a lazy river and both parks have a kiddie (under 48") area and a family raft ride. However, the BB family raft ride is MUCH longer than the one at TL. You exit in water that is only about knee deep on this ride. All of us went on the BB family raft ride many times, but they only wanted to do the TL raft ride once.
On the BB lazy river I would guess that the water is maybe 3 feet deep or so - you'll easily be able to stand if you want to. The thing that makes BB better for older children is the Ski Patrol Training Camp which is aimed at children about 5 - 10yo. Both of ours loved this area (I think they were maybe 6 & 9 on our last BB visit). TL doesn't have anything similar, although it does have the shark reef which is pretty cool too. BB also has a chairlift to get to the top of the larger slides - good for tired Disney feet.
I find the walking/pool surfaces are a bit rough at both water parks, and for us water shoes are a must. Those water proof around the neck holders (available at shops at the water park) which are big enough to hold Disney passes and credit cards are a big help, too, but in order to keep money truly waterproof we wrapped it in a ziplock bag first before putting it into the holder.
Sometimes it just comes down to whichever one is open when you visit - usually each of them is closed 1 or 2 months a year for rehab.
Whichever you choose - have fun!
. The kids are 8 and I'm not afraid of the water. Do they have the lazy river type thing at both waterparks?
