I also agree with above, and particularly with mjm's comments.

Christmas Eve = Valentines day - high prices at restaurants and hotels with double beds that night as a result. A good evening to chow down on noodles or a MOSBurger for dinner instead.

Christmas Day (when many places take down their decorations/lights in order to replace them with those for New Year) can seem like an anticlimax.

Still, as both of these days are midweek this year and aren't holidays, the Tokyo Disney Theme Parks might be the best ones to go to experience this festival.