Snow vs Winter
In Canada, there is now a symbol that has a mountain and a snowflake, and that symbol is associated with standards for a winter tire. M+S standards are very loose, and are not good enough to be called winter tires.
I use ice tires, and when I take them off in spring, I miss them (Michelin Alpin). The Goodyears that came with the PF are so-so. I'm sure the Pirellis would be great replacements for MO's original summer tires (M+S is a 3-season tire), but ... snow, winter, ice... those are real winter tires, esp. for Canada.