Les Chefs is a must do for us. Mama Melrose isn't authentic Italian...more like your run of the mill chain restaurant like Macaroni Grill or Olive Garden.
Chefs de France is my FAVORITE place for dinner at EPCOT. We are filet mignon and onion soup people and it was amazing! YUMMY! You are making me hungry!
I just want to add that I'm not bashing MM, as I am making an ADR there for our next trip. But if you can only do one or the other Les Chefs is definitely the one to go for.