How many miles are you putting on them in a year? Unless you do some serious miles I don't think diesel will pay off unless you have an in house mechanic that can do all the small stuff for you. You pay more for the fuel but gain longer service intervals with an engine that will likely last 300k+ miles before you need anything major done to it. Downside is just about everything else maintenance wise is more expensive. If you put enough miles on them its worth it but if you don't then they are just pigs.