I have the Schwalbe marathon winters on my cyclocross bike, which I use primarily for my long training rides. They've handled pretty much everything, except for deep frozen sludge and ruts. But because I pick the time/place for my training rides, this has been a non-issue.
For everyday commuting, I still prefer my singlespeed mtb, with the Schwalbe Ice Spikers. I've gone through everything with these, not a slip. I find that when roads get really icy/slushy, nasty potholes and cracks get hidden, and the wider mountainbike wheels can just roll over without problems.