I gues it comes down to the use,
we have a petrol V6 (bought 2nd hand) and while it guzzles when towing, we only do about 11,000 k per year so if I consider the lower buying cost (like... thousands), lower servicing costs against the distance travelled, I think we are OK
If i was doing high mileage I'd have to at least consider the diesel for sure as the economy and resale would offset the purchasing and servicing costs