We just ate at Brown Derby on Saturday and I thought it was great. I'm not a big buffet person though, so I didn't consider H&V.
It was a lot of food though, even for the kids. They all had chocolate milk, chicken noodle soup, dinner (two got fish sticks, one chicken nuggets, but they had other things on the menu - a lot to choose from, as far as Disney kids meals which on the whole are kind of ho-hum to me) and then dessert.
I had the salmon and it was excellent. Yum. Honestly, it was the best meal of the entire trip!!
We didn't end up even needing the Fantasmic package though as the 9pm show was rained out and a LOT of people left. The 10:30 was a go, but it was iffy and I don't think people wanted to wait around that long.