For sweaty activities, Gor-Tex can't be beat. Snowmobiling is definatly a sweaty activity, and the premium snowmobile clothing is almost always Gore tex. It vents off the sweat vapor while remaining water proof. In my shell, I can lay on the snow and remain dry. Now cold is another matter, you definately want some insulation to keep you out of the cold and water your body heat and weight will probably create.