La Clusaz is nice. I've heard it doesn't always get the best snow but the village is really cool.
I don't know if it's open in winter, but if it is, you have to do the via ferrata: it is awesome! it's like 300 feet high and the view is gonna blow your mind.
the park is good, its pretty small, but it normally has a decent size jump or two, a bunch of rails and a pipe that you can shesh at night....i believe.
do not i repeat do not go there for park, try maybe les diableretes for park or something else, the mountain at la clusaz is huge and it is a terrain park in itself