i don't mean to bust in on a conversation with people i've never met, but when your talkin diesels i perk up. I sell fords. I ,personaly, would not buy the 6.4l diesel yet. I stress yet. I have a 6.0 diesel right now. Happy as all get out. The guys that have driven it stock thought there was aftermarket work done to it. It was stock. I bought it used, and yes, it has had all the problems that were indicative of this engine prior to me owning it. But so far, since I've had it, no issues. And i've worked it harder than its ever been worked. In the winter I plow with it. A 9.5' steel western v-blade. In the better weather I tow 11,000 lbs worth of jeep and buggy for long distances. With a Hyperpac and 4" turbo back exhaust, empty, i get 18 mpg around the country roads and 24 mpg on the expressway. 17 mpg towing and 13 plowing. I am very happy with the 6.0.
Rumor has it that Dodge has given up the Cummins and is going to put Volvo diesels in their pickups. Ford has available in f250/f350 the Powerstroke. F450/F550/F650 available (jumping through hoops) are the Powerstroke, and Cummins. If you have a much larger budget F550/F650 has an available CAT Diesel. Yea I said a CAT. If you a fan of the trucks that blow black smoke, Ford is where you need to be.
Notice i didn't say anything about Duramax. Enough said.