Granted, I have not eaten at Monsieur Paul or Takumi Tai, but excluding those I would say Tiffin's is better than any other Epcot restaurant.Best in-park on WDW property. That should be a poll!
If you excluded EPCOT, I may even agree.
Certainly better than Chefs de France, Via Napoli, and definitely better than Le Cellier. But then, I've never understood the fascination with Le Cellier - it's mid-quality, USDA-Choice steaks in a loid, crowded space.