Lol, I don't really care if you think they're "substantially" better, they weren't better in new snow when I rode them. Whether they're better in other conditions like icy ruts I don't know.

Only tire I've ridden that's been "substantially" better than the marathon winters was a Pugsley (Fat Bike). With a 3-4 inch tire, and you can ride in snow, over ruts, and over everything but the sheerest of ice (though now they have studded versions of their tires, so they can even handle that...). Even with those though - it will only handle 6-12 inches of snow (depending on the type of snow, temp, etc).