The "3PMS" (3 Peak Mountain Snowflake) is a performance certification. The tire line will have been tested and passed a certification. It doesn't matter whether it's sold as a winter tire or all-weather, it's purely test based.

Among tires with the 3PMS, they might exceed the test standard by various amounts, but that's going to need individual tire reviews and Consumer Reports or something. Any 3PMS endorsed tire should be good in poor winter conditions, but some will be better than others.

As an aside, I usually just get All-Seasons M+S or whatever All Weather tires are on sale nowadays. My secret is I don't drive on the Malahat or the Coquihalla in winter conditions, and I'm not passing anyone in a snowstorm. Plus I don't live in northern BC or Alberta. I used to carry tire chains in case I got caught out by a sudden storm or freezing rain, but I haven't done that for a few years. I should get new chains. I will also say that when I was in northern BC, AWD or 4WD made a big difference, on top of tire selection. I don't have AWD or 4WD now, so I double drive more cautiously in winter.

A final caution, even the best winter tire will perform worse than a bald tire in summer, and even 4WD is simply reducing the performance hit. My impression from seeing cars in the ditch up north is that there were just as many 4WD and AWD vehicles in the ditch. You can do 90 kph along a clear stretch but then hit a small snow drift on a corner or patch of ice. Just because people are passing you doesn't mean they are driving to the conditions.