I have previously owned other German makes (Audi, Volkswagen, and Opel) as well as a Mitsubishi 3000GT in Dodge drag (aka Stealth) and can honestly say that I have never loved any car of mine as much as this E320 Mercedes-Benz (although I did lust after an old girlfriend's TR-6 30 years ago). The combination of reliability, luxury, performance, and economy (23 mpg commuting and 27 mpg on a recent aimless and leisurely drive with my wife through the countryside with the windows down and the sunroof open) simply cannot, in my estimation, be beaten.
I was somewhat leery of how it would perform in winter conditions, being rear-wheel drive, but with its traction control, ABS, and ESP systems it proved superior or equal to other vehicles I have driven in the snow that were FWD and AWD (although not all, obviously... I have owned various Jeeps, true 4WD Subarus and Isuzus, and a 1971 Land Rover Series IIA, but that's all in a different league and another story for another day). On one particular snowy and slippery day last January before the plows had gotten out, my wife was out in her FWD Chrysler Concorde with traction control at the same time as I was out in my Merc... we had very different experiences; mine a vague occasional "maybe" slip while she was slipping and sliding all over the place. I can only wonder how the Mercedes 4MATIC AWD system performs...
I know that inevitably some people will end up with the rare "lemon" and that others will have run-ins with dealers, but in the year that I have owned my E320 I have nothing but praise for both the vehicle and dealer service, and it has required nothing above and beyond normal maintenance.
PS - The only time I get to really enjoy the acceleration available is on highway entrance ramps (I mean really - you can't try to best your 0-60 time out of a traffic light on Main Street, can you? Not without unpleasant repercussions, anyway). Just last week I was behind a balding guy in his midlife-crisis BMW Z-somethingorother convertible (I didn't notice the actual model) and as we went up the ramp he was obviously into the same frame of mind... a puff of smoke came out of his exhaust and he took off like a bat out of Hell. I floored the E320, batted the gear down to almost redline and crawled up the BMW's backside while listening to Beethoven's 9th blaring over the Alpine stereo with Bose speakers, then passed him at almost 100 mph. Priceless. I love this car.