Jake,and Pelican,from info i see in the TDR,the guys with Dodge's that Hotshot around the country ,in there travels,talk to owners of PSD's that do the same.From what is in the mag,the PSD is usually good for about 425K max when hotshotting.The Cummins in the Dodge is good for 800K-to over 1 million,before they require a rebuild.This is running at 12-25K GCWR every day.All the diesels seem to love to run nonstop,and last much longer on the open road than local driving.Now the Cat is probably going to last at least as long as the 5.9 Cummins,probably longer,since its bigger.Dont forget in an F650,the PSD will not last nearly as long as in a pickup,due to the weight.If you notice you cant get a PSD in the bigger Fords,but the 5.9 Cummins and CAT are in them,that tells you something,the PSD is at its limit in the F650,and while it will work,if you ever want to tow a 10 ton trailer,or sell it,or run loaded every day,your going to regret not buying the CAT.Why put a light duty engine in a medium duty truck.When you look at the unfront price vs power/durability/resale,the Cat makes the most sense for most big trucks.Whichever you choose,you will own a fine truck,and good luck with it.