By far, the best TS at Epcot is Bistro de Paris. The food, atmosphere and service are on a different level from all of the other restaurants. My favorites, in no special order, are Chef's de France, Rose and Crown, Marrakesh, Le Cellier, if you can get in there (although I think that it has gone downhill since the
DDP, it seems more crowded now), Biergarten. Mexico is ok, but I'm not in a rush to get back to it. Alfredo's, ok, but the service is not as good and the food is just ok.
If your in the epcot area, don't forget that there are plenty of restaurants just outside the international gateway (ESPN, Big River Grille, Yachtsman, Flying Fish, Palio's, Blue Zoo, Shula's)