I was out with the bicycle with the Schwalbe Ice Spikers on it this afternoon and got caught in some freezing rain. I stayed out long enough for the ice build up on the helmet and bike to be noticeable. The traction on wet shiny roads with some ice was as I had expected it would be - perfect. It was no different than if it was just normal rain.
So far, several hundred km into the tires, I have not lost any studs (or rather, I lost three of them due to getting caught in a rut made between the concrete curb and the asphalt but was able to pick up the studs and reinstall them). There is no visible wear on the tires or studs yet despite being driven mostly on asphalt.
I did get out in some snow with them. That slippery wet stuff that builds on the roads in minutes and sends cars sliding in all directions unless drivers are very careful. Again, the bike handled it as if it was bare pavement. Acceleration was without slip, stopping was easy and stable, and steering better than expected. It is the steering that is tricky. Care needs to be taken compared to dry pavement (master of the obvious here) but the margin of error is much higher than it would be with standard off road knobbies. My biggest concern in snow like that is other traffic. A bicycle equipped with Ice Spikers is more stable and handles better than a car with snow tires in such conditions.
The studs on the center blocks have settled in very very well and are not protruding as far as they were before (it is not wear I am seeing but a settling in of the studs - they tend to settle in splayed to the side since they do not get pressed in straight due to the curvature of the tire.)
Verdict so far? Astonishing grip in the snow and ice.