We have gone several times just before Xmas and twice during the week of Xmas.
Frankly, we love it. Yes, it is crowded. Yes, it is noisy and yes you will have to wait for everything.
If it is not your first time and you are not the kind of people who feel you have to ride every ride you will probably have a lot of fun. There are a lot of special events that go on the entire period. Epcot has special "Santa" storytellers who perform in costume and tell the legends in their country. There are special holiday meals and all the wonderful decorations are spectacular. Each resort has special performances and events for the children.
The resorts are not discounted during this time of year. The whole week is busy as they also have a lot of special events for NY Eve. I have found most people to be more relaxed and happy during this time. Maybe because I was just so happy to be at my favorite place that I feel this way.
We tend to spend a lot of time at Downtown Disney and go to a movie and enjoy the singers they have performing. Really, if you stay on property and don't have to battle the traffice or parking it isn't that bad. Well, busses at the end of the day when everyone is leaving, that's bad.
We relax, plan our meals ahead and just go with the flow. Remember, they have special parades too. I think it is worth doing at least once.