We just went from Dec. 13-20.
The waits for rides didn't seem that bad, except all the headliners. It was difficult to get a "good" 4th FP, and we really did a lot each day.
It was more crowded than we expected, but mainly in the walkways of the parks. It was super helpful for us to be at Rope drop, we did so much in the first 2 hours, then really had to slow down due to crowds.
We also found that the last hour the parks were open were also a great time, but we traveled with teens, so we could keep the candle burning at both ends. For us Disney is not for sleeping! We can do that at home.
It really was a magical time, we LOVED all the Christmas activities. CP, Light at HS and
MVMCP. The trees and decorations were beautiful, and the castle is breathtaking!