Which meal are you looking for? And are you wanting a character experience?
Ultimately, we're not as big on the dinner buffets b/c the food doesn't always seem to measure up to dinner at a menu spot, but Boma and Biergarten have been some of the more enjoyable dinner buffets we've experienced (although, it's been a while since we've done Biergarten). I don't really classify Akershus as a buffet since you order your entrees from a menu, but the cold buffet (which is essentially serves as appetizers/salad) is nice. I guess there's also family style all you can eat options like 'Ohana and Garden Grill.