I have a pair of Schwalbe Winter marathons for my main commuter and a pair of the Nokians for my xtracycle. The Schwalbes are a bit better on the rolling resistance, but both are very good for icy conditions and the Nokians have some extra grip for snow, so there is a bit of trade off there. One thing I have found is that it is important to remember that your *shoes* probably do not have studs, so it is important to be very careful after coming to a complete stop!