Plan on going the week before Christmas this year. It will be our first time going at that time of the year. Can't wait.
We were there Dec 3-9. Although it seemed like there were tons of people in the parks - we didn't wait long for many rides. We used FPs for the headliners and never waited longer than 10 min for most rides. We waited 20 min a couple of times, but not much. The lines may have gotten long in the afternoons, but we would hit the rides in the morning or whenever the lines were shorter.