It's all subjective but there are a couple I have feelings about....
Tusker House in AK. It's a buffet with characters. It's nicely decorated and I'm always fond of AC anywhere at AK. But the food is bland and weird. It's supposed to be Indian or African influenced, but it doesn't taste like anything but squishy with coconut milk. It's like Vegas Vacation - "I'll have some of the yella".
Another loser for me is Garden Grove. Another buffet with characters (but run by Marriott). My family went there for dinner a couple of years ago. It was very low-key, that's great. But the characters were extra dingy, like the costumes were cast offs from some better character meal. Otherwise, dinner was strangely reminiscent of Thanksgiving dinner at a Howard Johnson's restaurant in western Pennsylvania in 1985..... Sliced roast beef, mashed potatoes, shrimp cocktail, vegetable soup, mountains of dinner rolls. It was good, but it wasn't. The highlight I suppose is that I think Marriott does a much better job of buffet desserts than Disney. Disney desserts seem like a lot of beautiful cardboard sometimes.... Marriott kicks some cake butt.