I second the transportation - it was great! We were back to our resort in a half hour from DHS on New Year's Eve they had so many buses after the fireworks.
Everything is open and open extended hours. Want a Dole Whip for breakfast at 9:30 am? No problem.
I thought the crowds were friendlier than they have been at other times of the year.
TONS of international families, but I didn't see a single tour group.
Extra entertainment - 3 Fantasmics a night, 2 afternoon parades, 2 Light Parades etc.. made the scheduling much easier.
If you can handle burning the candle at both ends, you can do it all. It was a little tough getting up in the dark. But being in MK as the sun rose was a wonderful experience.