When I was crossing Canada by car (in winter), I decided to spend Christmas in Mont Tremblant. It was one of the highlights of my Canadian trip!
I can still remember the peacefulness of the resort and the laughter of the children with Father Christmas (in person) waiting calmly to hear the children tell him about their year and the presents they were hoping to receive.
I can also remember evenings of great food followed by days on the snowy slopes, at a very reasonable price compared to what I've paid elsewhere...in France, for example!
I would say that the Mont Tremblant ski resort is a great place to relax and enjoy the Quebec winter.
When I lived in Montreal, I often went to Mont-Tremblant for a whole day of skiing.
If you're touring the entire country, the resort isn't as good as those of the Rockies in British Columbia, but it's still a great place to ski on a weekend in winter when you're staying in Canada.
It's a ninety minute drive from Montreal and I'd advise you not to go there at the weekend when the slopes are full of families and tourists.