The operating hours will be shorter, and there will be less entertainment than other times of the year. There will be more rides down for their annual servicing, and the weather can be unpredictable. But the benefits far outweigh the negatives. We love traveling to the mouse in early Feb. Crowds are low, especially during the week, and many rides are 15 mins or less line ups during the week. The weekends do tend to be heavier when it comes to crowds, but that's common most weekends at DL during the year. So long as you are prepared, and watch the underground weather just before you go for current up to date weather, you'll be fine. It's a great time to go. You may want to consider a Character brekki if you are really into meeting Characters, and there are many good ones to choose from.