This is tough for me, because I have eaten at both fairly recently and I like both for different reasons!
I'm going with BOG, because I've had 2 out of 3 meals offered there and they were both delicious. My husband said the lunch there was the best meal of our entire trip, and that's saying a lot.
I've only ever had breakfast at Crystal Palace, and while it's one of my favorite character buffets - the breakfast I had at BOG was much better!