By "winter" ... Not sure how MrWizard determine that? By the snowflake rating? That's how I do. Also I look at manufacturer rating for all the different road conditions.Concur ! "All season tires" are mostly marketing hype. The best you can hope for is a couple of deep, continuous channels around the tread that will let water out (prevent hydroplaning).
Yes ! There have been studies that show "winter" tires (not M/S or "all season") on a 2WD vehicle perform better on hard packed snow and ice (what typical driver encounter the most) than any other tire on a 4WD vehicle !