I can't speak to TDB because I've never even heard of it before, but from what I gather from the previous replies, it's a Brazilian Steakhouse, I'm guessing similar to the Fogo De Chao chain?
I really enjoy Ohana. It's a great family atmosphere, the food is excellent and oh so plentiful! There are many activities to keep the kids entertained. Also, afterwards, you can go down to the beach and watch Wishes from there, if you time your ADR correctly.
I've been to Ohana twice: Once as a teen/kid with my parents. I LOVED the pineapple and caramel dessert (which they don't have anymore, but I still remember it 15 years later, so that's sayin' something!). I also went when we took DD (6 at the time) for her first trip in 2010. We pushed back the ADR to 9:30 so we could see Spectramagic. By the time we got to dinner, out hunger had passed, so we all pretty much picked at our food. DD had a delightful time participating in the live entertainment (Hawaiian woman with a ukelele - totally entertained all the kids!), and the little food we did eat was delicious. We felt guilty wasting all the food!
I think it would be a lovely celebration of your DH's 40th. jmo. I'm sure the other would be great as well, but Ohana seems like it would give it a more "family" atmosphere.