I doubt either week will be very crowded. But Universal doesn't start their Christmas stuff early like Disney does, so if that interests you at all, you may want to go after Thanksgiving as opposed to before.
I told husband to call and ask about hotel prices since we got a card with 35% off in the mail today. He got off the phone and had booked it for the week after Thanksgiving - so I guess that's decided! That's the first thing done for planning out trip. Let the fun begin!