Big Mountain is found up near the Canadian border in Montana. This unfortunately means that it's a somewhat isolated spot. As its name suggests this is a fairly substantial area, with 3000 acres of skiable terrain. All abilities will find plenty of decent challenges, from excellent beginner runs, to great cruising, to awesome steeps and powder for experts. All this is served by a highly efficient lift system and a great snow record. The locals are very laid back and welcoming. Off the snow you have 2 choices of base. You either stay 12km away at Whitefish, with its better après-ski and range of non-skiing activities, or stay slope-side at the 'Alpine Village'. This obviously means better access to the skiing but at the cost of fewer après-ski opportunities - it's also more expensive than Whitefish. As with all North American resorts, ski school and childcare are first-class.
Two more things… First, Big Mountain is the major focus for telemarking in the US and this makes a great alternative on the slopes. Second, Big Mountain can suffer from bad bouts of fog, creating some, um, interesting conditions.
Overall, this is a great ski venue, perhaps best visited in tandem with Canada's Fernie. It is miles from anywhere and would make a better choice if you had 2 weeks rather than 1 to spare.