We've been to both of them many, many times. Big fans. Frankly, they're both fantastic and have similarities, so you won't go wrong either way. If I was forced to pick one for thrills sake, I guess it would be Typhoon Lagoon, but by a margin of 51%/49%, because I don't want to slight BB. BB has plenty of thrilling things to do. Summit Plummet and Slush Gusher are awesome. But TL has Humunga Kowabunga and also has Crush Gusher, which is a very unique group of slides (jets of water propel you forward at times). Then of course, the grand daddy of all wave pools is at TL. It's amazingly awesome! I've never seen another wave pool with waves this big and powerful. If you're going to go into the deep end, be sure the teens are really strong swimmers. But if you are a strong swimmer, it's so much fun. Even if you aren't a strong swimmer, stay in the shallow and you can still enjoy it. The bottom of the wave pool has a very rough surface. Try not to fall down and get dragged by a wave. I've had skinned knees and elbows more than once.
Both places have plenty of chairs in the shade, you'll have no trouble finding a spot. No need to show up 45 minutes before park open. Just show up 5 minutes early and you're golden. The first hour you can ride the slides over and over with no wait. Head for the big slides, because the lines get super long later in the day, and there is no FP+.
The pavement can get pretty hot. Some people wear water shoes of some type. I personally despise water shoes and would never do anything but go barefoot. But just be aware the pavement can get hot. They do a good job of wetting it down, but there will still be some hot spots.
