The monorail is great, but the boat from Wilderness Lodge can be just as efficient. Taking the monorail to the Magic Kingdom, it will be the 4th stop from the Contemporary.
To me, one of the biggest advantages of the Contemporary is the walkway to the Magic Kingdom- which can be even shorter! You can quickly walk to the Magic Kingdom in the morning when you have energy, and at night, you're the first stop back on the Monorail to quickly return to your room.
Theming wise, both are great, and come down to personal preference. The Wilderness Lodge is BEAUTIFUL during the holidays, and edges out the Contemporary just a bit there. Although the giant Mickey wreath on the side of the Contemporary facing the Magic Kingdom is nice to come 'home' to at night.
I'll be there early December too- my favorite time to visit!