The counter service at the AK is the best of all the parks, IMHO - in fact, I think that the 3 you mentioned there (Pizzafari, Tucker House, and Flame Tree) are lightyears better than the only full service restaurant at AK (Rainforest Cafe).
Tucker House is fantastic and has vegetables (a rarity in Disney counter service), Flame Tree has good barbecue apparently (I'm a vegetarian so I wouldn't know), and Pizzafari is good but not really special or anything.
Basically I vote for Tucker House. Dont waste your money and time at the Rainforest Cafe. If you must, do the one at DTD - it's less crowded.