Yeah, different food. The Festival of Holidays is holiday inspired food from around the world, each booth with a different theme and the offerings will sometimes say what country they are inspired by. The drinks could be beer, wine, nog, non-alcoholic.
Food and Wine is mostly California inspired from things we grow here; olives, artichokes, garlic and I think every booth has at least one wine to do pairings. It's been a few years since I've been to Food and Wine, so this might not be the case anymore. Also, they have celebrity chef demonstrations and wine tastings led by professionals that they don't have during Festival of Holidays.
You can eat, drink and be merry at both and I've always found delicious things at both.