One of the best researchers on automobile quality comes right of my home nation of Canada. Phil Edmonston has published his "Lemon-Aid" guides for decades, and mixes real world surveys and letters from owners with statistical data.
Reading those books is a real eye-opener as to the quality of cars. He doesn't pull any punches. For instance, he feels the Toyota Camry is indeed a reliable, well built car, but has many problems. He talks about AC problems, head gasket problems, and body integrity being widespread problems for Camrys.
Toyota's secret of course is their willingness to repair things promptly for people, instead of making them angry by fighting with them, unlike GM, FORD or DC.
His take on Mercedes is that MB quality took a huge leap in the early 1990's with the move from the 190 to the C-Class, and the refinement of the W124 E-Class. Despite things like head gasket problems, the W202, W124 and W210 are some of the most reliable cars made. PERIOD.
But, what about Japanese cars?
Well, Phil noted that they are exceptional on initial build quality, but in year four to five, start to develop problems and will also begin to cost huge sums in maintenance.
Is this new to us? Nope.
He highly recommends the 95+ Class and 93+ E-Class cars. (In Canada, not enough S-Class cars are sold to make conclusions)
Are they perfect? No, but they are without a doubt among the best made cars available at any price.
After reading the DSB's (Canada: Dealer Service Bulletin) on the Honda, Toyota and Nissan products, I was surprised at the length and scop of the list. Head gaskets galore. AC compressors, condensors and evaporators. CV joints. Suspension components. Faulty electrical components. And on and on...
Want to laugh? Read the DSB list for the Intrepid or Taurus. Just make sure you've got some serious time on your hands, and either list is a novel.
Despite rattle-cage 98 ML's and some other stuff, I still think long term prospects are the best for MB when compared to other cars.
1998 C230 "Black Betty"