I have 20 years (well, seasons) experience with studded tires. The Nokian W106 is the most durable, good for 5 seasons. The Schwalbe Marathon Winter is better for ruts, rolls easier on both bare pavement and ice/snow, but is only good for 3. There is a tendency to lose studs. The failure mode for each is the same -- the studs push through the casing. I switched from Nokian to Schwalbe when my office moved to a location reached by rutted bike path from an earlier one reached primarily by road. A bike on studded tires is the best road vehicle, far superior to a car without chains. Unlike a car, it can always get you home. A modern road bike on slicks is basically unrideable in snow and ice. A hybrid or mountain bike is OK if you don't use the front brake or climb hills. The old balloon tired single speeds from the 1950s are surprisingly good. You can broadside drift through turns like dirt bikes. All of these, however, greatly benefit from studded winter tires. Riding with studs on glare ice is one of life's pleasures -- it is smooth and dreamlike. It is best of all when passing five miles of stuck cars.