All the crowd meters list it as really really busy. One of the busiest times of the year. I avoid these times of year, so I have no first hand experience, sorry.
We arrived on the Sat of Thanksgiving and stayed the following week after. Sat and Sun were busy but it didn't seem to be crazy. As it was colder the water rides didn't have much of a line (15min). Our longest wait was Peter pan (30 Min). Once Tuesday hit (after Thanksgiving) we walked on every ride (except Nemo- 15-20 min on a MM). Fantasmic and Parades were very busy. We had to get a spot for parade an hour before. We went to find a spot for Fantasmic an hour before and we couldn't find anything. Luckily a nice family invited us to sit with them otherwise we would have been standing at the back.