As with almost any used car. The quality of the vehicle is reflected by the past use or abuse. I have bought and owned over 500 used vehicles in the last decade... and damn near every one of them has been a daily driver for at least a few weeks ( I spend ALOT of time in my vehicles) There's a definate differance between a "polished-up nightmare" and a good quality car. I've got about thirty vehicles now (a three series and six series BMW's, a TT RX7, a TT 300ZX, a TT 3000 GT, a TT supra, a turbo porsche, a turbo eclipse, an RT / TT stealth, an IS 300 Lexus, a fox-body stang, a GTI/VR6 and a GOB of Honda and Acura products... but, I also currently own three benz's and I will say that every one of them is, and has been a great car. My kids have been running the crap out of an E 430 I got for them as a "high school car"... hell, they've even stuck a 100 shot of NITROUS on the car... it just takes it like a champ and has been doing so for over 30K miles now (even though the odometer shows a staggering 223,000 miles. I have a newer AMG. It's dropped to the ground on twenties, and also has NOS on it... hasn't given me so much as a "glitch", and I drive it fairly hard against the "vette and hemi crowd". I'm NOT just having fun writing this and trying to sound like a "big-wig"... but I collect cars of ALL types (old and new).  I've owned a car lot, an audio shop, and a vehicle performance shop for many years... so, I've had ALOT of experience with vehicles... and the picking and choosing process when it comes to buying a great USED vehicle... and there really is such a thing as a polished-up piece of crap. In the defense of a Mercedes... if the vehicle hasn't been taken care of properly for the first few years of it's life... like any other brand, it's gonna be a headache of a car, or possibly even ruined by the time the second owner gets ahold of it. Mercedes DOES put out one of the better products to date... In fact, after owning such a WIDE variety of vehicles over a number of years, it's my professional opinion that a well cared for and properly maintaned FOUR year old/70K mile Mercedes is still a better vehicle and an over-all better value than a BRAND NEW CAR from the BIG THREE ( notice in my list of current vehicles, I didn't mention many chevies, fords or dodges... there really IS a reason for that ) Yeah, I've got an old Bel-Air, and old Road Runner, an old Mustang etc.... but, shy of possibly a newer vette, viper, or Rousch stang... the newer domestic products just can compete with the level of quality that went into a two to four year older BMW, Mercedes, Lexus, or Acura... simple fact.