100% I love Boma and 'Ohana. Boma on rib night is my favorite on grounds by farBoma's dinner buffet at Animal Kingdom Lodge is probably my single favorite restaurant on all of property.
Whispering Canyon at Wilderness Lodge isn't a buffet per se, but it is all-you-care-to-eat. Good food, and tons of fun for families.
Same goes for Ohana at the Polynesian, which is even better, but considerably more difficult to get reservations for.