That's a hard call since both are excellent restaurants. Wolfgang Puck Cafe is one of our not to be missed and since Le Cellier has really gone down hill in our opinion, we feel Chefs de France is the restaurant of choice at Epcot.
I have had only excellent meals at both. I would decide based on your other activities you'd like to do and where you'd like to be. We would prefer Wolfgang Puck for the food, but to miss Illuminations (our favorite) would be not good. Not sure what DH would choose, but I'd be leaning toward Illuminations and Chefs de France.