Just got home after another 8km winter commute and my ride time was not much more than it is in the summer as my route was pretty clear... when I hit my residential neighbourhood I am always really happy to have the studded tyres as the roads are polished to a shine.

As far as flats and diy tyres go... I have had one winter flat in the last 5 years of winter cycling and usually ride 5000 - 6000 km every winter.