Come on guys, I think it is pretty obvious that winter tires are superior to all season tires for snow. Here if you don't have a tire with the M+S symbol and police stop you or you have an accident, then you might have trouble.
All season tires is just a compromise for the Winter. My Forester came with all season tires, because it is cheaper than to swap tires every year or pay to store them during Summer. Some people do not have their own garage, so they have to pay for storing them.