If you're interested in ONLY MK restaurants I would recommend Liberty Tree Tavern and then Skipper Canteen.
LTT is an all-you-care-to-enjoy meal. They bring it to your table and if you want more they'll refill the bowls. Usually you're served three meats. Roast, pork loin, and turkey or ham. You will usually get a bowl of dressing with a gravy boat, a bowl of macaroni and cheese, usually green beans or corn, and we've also had sweet potatoes that were amazing and I hate sweet potatoes. They serve salad and rolls. Then they have a giant toffee chocolate chip-type cookie sundae on a skillet for dessert. It is all fantastic. The restaurant itself has a colonial theme. We've never been disappointed there and my small children even love it!
Skipper Canteen is themed off of the Jungle Navigation Cruise ride. It is decorated so well and your "Skip" (or server) is super corny just like on the ride. It is very fun and funny! The food there, in my opinion, is for a more mature palate. For instance, the side with my steak wasn't just plain ol' mashed potatoes. It was a mixture of mashed potatoes and mashed plantains. It was very similar to mashed potatoes just a tad sweeter. They have an amazing chocolate, banana, and cashew dessert there called Kongaloos! that if you have no allergies and like those foods, I beg you to try. It is amazing! Anyhow, the food is just a bit more adventurous there. My example of the potatoes and plantains was a more mild one, too.
I would say, think about the kind of atmosphere you want and how much food you want. Do you want a ton of food or just a meal to order off the menu? Do you want familiar and comfort foods or some new and more exotic foods? Both of those restaurants are wonderful to try at least once, I say, for sure! If you're willing to travel outside of the Kingdom then that leaves you with so many more choices!
Good luck deciding and have fun!!