I know there is no correct answer to this question because we are dealing with opinions here. I love the diesels but both parents have w123(D&CD both around 200k). They are slow and they stink after a while like diesel. The newer(97? up) have the turbo diesels pumping out 175+hp. Now that is a car but I can't afford one yet(too new). As far as reliabilty goes, this is why we have Benz's, reliability. Gas or diesel are both good for at least 250k. My bud's mom had a 85 500SEL with 330K before she sold it and the heads were never off.My uncle supposably put 800k on a 350SDL before it blew and he put a new motor in it. I only have 66k on mine and i plan on getting at least another 100k before I sell. Love that damn car! So what am I saying? They are all great!