Our family has been going in Dec. for years. We used to arrive the week before Christmas when our kids were still at home. We would head to WDW just as soon as the kids started their Christmas break from school. It has always been our favorite time to be at WDW! We have many fond family memories. We would always leave for home on Christmas Day. The crowds generally would be low until Christmas Eve.
Now that the kids are grown we take two trips. DH & I go for a week by ourselves. We generally will go either the week after Thanksgiving or the week after that. It depends on our annual passes. This has been a wonderful time to go but I do believe it is becoming more and more popular. That being said, our second trip is with our kids and other extended family over the long MLK weekend. This weekend seemed to busier to me than our week in early Dec. There again, we had no problems with waits.