Its scary - 6.0 Fords have head gasket, egr gooler, and other problems...6.4's are supposedly nightmares too...All the mileage ratings are down across the board.
Even the fleet and heavy truck guys complain that the newer engines have become "fragile" (their words) since the addition of emissions equipment, and their mileage is down as well. In an industry where 1mpg is a big deal, its scary!