I've always used Nokian Hakkipillta W-106. I put them on in December and take them off in March. They are well suited to the icy freeze and thaw conditions we have here. Simce my normal tires are Schwalbe Marathon Plus semi-slicks, the W-106 are also an improvement in snow.

Last year, I tried Schwalbe Marathon WInters. They have less rolling resistance than the Nokians. I bought them because the commute to my new office involves a MUP which evil joggers chew up into an icy moonscape. I figured that the higher stud count and presence of edge studs would be better for riding in and out of all the craters. The jury is still out, because last year had very little snow. However, when the season ended, I was amazed by how many studs had fallen out. My impression is that they outperform the Nokians, but have a quality problem.

Last winter wasn't entirely a bust. Our one snowstorm was very intense and brough a lot of ice with it. Traffic came to a sandstill and many people who tried to drive home along my route got stucks and spent the night in their cars. In contrast, it took me only a few minutes longer than usual to get home. It just takes one evening like that to make them worthwhile.

Some studded tires do not have carbide studs. These will wear out almost immediately and are trash. Nokians typically last at least 4-5 seasons.

Paul