Forum members from countries that have proper winters obviously have their time-tested solutions either on a voluntary basis or as a legal requirement. Here in the UK a light dusting of snow on our roads is the stuff of nightmares and a settling of as little as 10mm will bring about a level of carnage not disimilar to the opening 10 minutes of Saving Private Ryan. Slowly we are waking up to the fact tyre choice will produce varied handling characteristics at temperatures below 7C.
"Red Ken" has the Off-road Package and Air Suspension so Mercedes shod it with Hankook Vento S1 Evo2 235/60 x 18 V-rated tyres. They are a Korean manufacturer although the tyres are moulded in Hungary. What surprised me is that these tyres are rated as "Summer" which means there will be a very dramatic performance fall-off at below 7C. I daresay Mercedes would happliy sell me a spare set of "Winter" wheels for around GBP1000 per corner. Luckily I also have a 4WD pickup truck shod with B.F. Goodrich All-Terrains which is probably better suited to and more sacrificial for adverse winter conditions. I gather the other OEM tyre fitted here in Europe is the Yokohama Advan Sport V105S which again is rated as a "Summer" tyre. I assume having 2 tyre suppliers is just to ensure stock availability.
I think when the time comes to replace my Hankooks I will try the new Michelin CrossClimate tyres. Although technically a summer tyre the new rubber compound, together with the arrangement of the sipes in the tread, gets them "Winter" tyre accreditation in countries where this is a requirement.
I've always had dedicated winter tires because Canada. Not taking any chances on the roads when winter comes and Michelin has not failed me yet. Was looking at the Latitude Alpine but haven't come across reviews for them yet.