I recently started a thread about the same thing!
Yachtsman is our must do! But I was looking to try Le Cellier until I saw they changed their signature dish, the filet. Seemed like the only thing people recommended. I read a few reviews and almost every one said the new sauce and risotto was not good & bland. Someone on these boards said the same thing:
Check out my thread:
http://forums.wdwmagic.com/threads/le-cellier-truffle-butter-or-bust.886799/
Personally I can't see going from Epcot to Yachtsman just because of the dress code.
We tend to head to Yachtsman after a day at AK, the water parks, or our arrival night.
It tends to take about 2 hours and then we spend time wandering the Boardwalk.**
**Which might allow you to see the Xmas decor in those resort since you will be there in December