My main problem with Consumer Reports' road test ratings is that they never provide the formula used to calculate scores. I asked one of their road test engineers why. His only response: "it's policy."
Without knowing this formula, their ratings aren't all that useful, as it's not possible to tell how closely their priorities match your own.
But even so I have far fewer issues with their ratings than their reliability info.
Note that Consumer Reports' annual auto issue includes reliability ratings for the year ending March 31, 2006. The data on which their reliability verdicts are based is nearly a year old.
Because our surveys at TrueDelta.com are more frequent, and we analyze the data promptly, our results will average over ten months' "fresher" than theirs. I've already posted results for the year ending December 31, 2006.
When considering a car, do you want to know how reliable it was a year ago, when it was a year younger, or how reliable it has been recently?
Vehicle Reliability Research
No results for any Mercedes models yet, as too few owners are helping out. Maybe with the next update, in May.