Hands down the best winter/snow tire you can purchase if your car can mount 17' wheels. I just traveled up the east coast during this past week's major snow storm that hit the south/mid-atlantic (2/13/14) and I never had a moment where the car felt out of control or that I could not traverse a patch of snow or ice. My experience is that of a car with AWD so that being the case these tires made it feel as though I was on a regular surface when trouncing through half a foot of powdery snow.
These tires can give a sense of over confidence though, because they're so good at stopping you and at getting traction specifically. This doesn't mean you're impervious to very deep snow or won't get your car stuck doing something stupid. What it means is that you're more capable of getting around in heavy snow with these tires then arguably any other set here on Tire Rack. Yes, they are that good.