I have same opinion on diesel trucks. For me, they don't make sense because I don't haul a big trailer (fully fuelled boat is just barely 3000 lb) and I only do the average 20,000 km a year, with about 2000-2500 km of that being towing. The auto makers charge a premium of at least $5000 for a diesel and they don't have enough of a fuel economy advantage to pay off that premium, at least not at 20K a year. $200 oil and filter change lengthens the ROI period even more.