We've been both times, and as far as crowds and weather go, both times are pretty much the same. However, if you want a holiday vacation, go in December. During December, Disney has an afterhours celebration (you have to buy seperate tickets) called Mickey's Very Merry Christmas Party on selected nights, and it is definitely worth going to!!
Biggest problem with going in Dec. (at least to me) is getting back home and getting ready for the holidays after the vacation. Sounds like no big deal, but with children, family, and holiday preparations - I was exhausted after it was all over. It was just too much too close together. Just consider that when making your plans especially if Christmas is a BIG deal for your family like it is for ours.
One of our favorite times, however, is early Nov. (around Veteran's Day). We've been several times at this time of year. Crowds aren't bad, weather is nice, and you don't have the big holiday rush when you get home.
This year we are going at the end of Oct. into early Nov. We'll be going to Mickey's Not So Scary Halloween Party! Happy Planning!
