I've started using MWs in winter here in the UK. Most of my 50mile (round trip) commute is on paved roads, but around 5-6 miles is black ice with 1-2" of snow. Terrible conditions for non-studded tyres.
This is my second season of using the tyres (26"x1.75"). Usually run them at 70psi.
After about 3-400miles I'd lost 14 studs. Contacted Schwalbe who sent replacements, free.
For those who wonder, I believe the MWs are based on Marathon XR tyres, not the standard Marathons. Very different tread pattern.