With young kids, I'd recommend Sci-Fi. I actually thought the food there was surprisingly good - I was expecting basically a slight step up from fast food, but the ingredients were all noticeably fresh and the food was all flavorful and delicious. Hollywood Brown Derby is more fine-dining style food, and while yes, it's much better than Sci-Fi, I still adore Sci-Fi. It's more fun, for sure, and the food and atmosphere are both more kid-friendly.