We did 12/30-1/3 this past year. Loved it, had a great time. Not so sure that time period would be my choice if we were infrequent WDW travelers, but we had a lot of fun and it was perfect for the way we tour.
Totally agree with
@Disneylover99 - the vibe leading up to New Years was great.
Don’t get me wrong, it’s crowded (especially NYE), but with the exception of NYE itself I found conditions on the ground weren’t nearly as “bad” as it can sometimes seem from reading reports around here.
But you definitely need to adjust expectations accordingly.