I gotta defend the 4 matic-I LOVE mine-I have driven it thru snow it NEVER should have been able to go thru-the instant on 4matic-combined with the light warns you of a few things-
like-hey the car is hydroplaning-hey off of the gas stupid-you are on black ice-or hey you took that corner wayyy too fast..
Yes it is expensive to maintain-and YES I did pay $1800 to replace the whatever it is part that goes on all of them (I am having a mental lapse here) BUT still I feel that for a car with 225,000 on it-it hasn't been all that costly....in all that time it broke down only ONCE (and that was a seized air pump).
I am a firm beleiver that an on-demand 4 wheel drive system really improves the safety of a car-without eating up tires and sucking down gas the way a fulltime system does-my NEXT car will be a 4matic also-only a station wagon....