Been to both, including the character breakfast and dinner at Tusker House, and lunch at Yak and Yeti.
If characters are your thing, you could try to get a reservation for a late breakfast at Tusker House (Donald's safari breakfast). There's plenty of good snacks and counter service in Animal Kingdom Park where you could get a quick bite later to hold you until your Chefs de France dinner.
Tusker House (lunch and dinner) has an awesome buffet with very delicious food. Being a buffet, you might get in and out faster. But for me, the food there was so good... I had to try everything... and I stuffed myself. We were there for dinner, but had it been lunch, I wouldn't have been hungry at dinner time!
Yak and Yeti is likely to be more expensive depending on what you order. But for us being on the deluxe dining plan, the price was all the same. The deluxe plan includes appetizers too so we tried some different things. The food and service there was absolutely delicious, and outstanding. We are booked again for our next trip. I have heard advice to avoid the usual kind of foods like Lo Mein or sweet and sour chicken. Most reviews I've read match my experience that the more unique entrees are much better. I highly recommend the Ahi Tuna and lettuce cups appetizers, and Mahi Mahi or Malaysian Seafood Curry. For dessert, the fried wontons were delicious!