I live in Montréal, Canada and own a '93 300E 4Matic. This is the best car I've had for winter driving. Unfortunately, it appears that a lot people neglect to check the transfer case oil regularly and this can lead to major repair costs. If you do decide to buy one, make sure that you have the AWD checked thoroughly. Also, they are prone to electrical problems but so are a lot of the MB products. They were often purchased as a winter car in the Northern States and in Canada so there are quite a few low mileage 300E 4Matic available out there. I got mine with 49,000 miles 15 months ago.
P.S. BTW, If you do a search on 4Matic on this forum you might just go for the Subaru