Fitted on Audi A6 Allroad Quattro (with Autohome roof tent). Used in the Alps in 10 inches of snow (max), steep icy/snowy slopes, uphill and downhill at speeds up to 40/50mph. Previously owned Michelin Pilot Alpine II on A4 Avant (non-Quattro). Comparison is very positive with extraordinary grip in deep snow and what may be difficult conditions without the Quattro/vredestein combination. Braking distance in snow was tight and always in control (ABS). Sharp starts are blistering as no slipping felt. Mornal / summer motroway driving / noise is very good for snow tires.
One drawback is wear: on this vehicle, it appears that the Xtrem4 do wear out on normal UK roads quite quickly. Hammerblow is relative pricing to Michelin's. Michelin's simply do not last twice not justifying the double price tag. Counter-intuitively, added advantage is that replacement is more regular that on the Michelin's - which keeps the rubber softness issue on your side. Overall, excellent tire for alpine use and confident in normal roads...