Depending if you go early during the christmas season celebrations, it is not too busy. I'd say it's about an average day at both parks.
Hulk maybe 20-30 mins, not too shabby of days.
If you come the a couple days before christmas till about a week after new years, it is usually pretty busy at both parks. Expect to see the summer style crowds at parks at that point, or a tad below what that is like anyways.
Surprisingly the best part during that busy part is the week between christmas and new years. after new years, forget it, or before or on christmas, forget it