I friend of mine has a 2003 F-250 with the 7.3L Diesel for sale that I am going to look at tomorrow. It has 75,000 miles on it, and I know it has had meticulous care (he is a retired heavy diesel mech...
You can hardly hear it (at highway speeds after it warms up), I never noticed a stink except when the front caliper stuck, and there can be a puff of smoke when it starts, but nothing after that. I call mine Newman! He is a cream puff, but I put Warn hubs on the front (you need to do that) and he runs like a top. Had him 12 years now, and not slowing down. About 115,000 miles.