An alternate line of thought ...
If the intent is to use the Polar Express set only with a Christmas snow village holiday display every year, then I suggest choosing the better looking train, which the Flyer set most definitely is. The Flyer set, particularly the loco, is much closer to the appearance of the Polar Express in the movie. If, on the other hand, this is an opening purchase for what is likely to become a larger and more extended railroading layout beyond the annual holiday snow village, then the O gauge route might be the more logical choice.
Have fun, regardless!