I've been involved with two Duramaxes and one Cummins and I think they both have advantages, but the advantages are in different areas. The Duramax seems to get pretty good mileage on the road (18) running empty and pretty decent mileage (13) when puttering around. This summer our service truck was a 2004 3_4 ton with a Duramax. It weighed 10000 pounds loaded with tools, compressor, welder, etc. Behind it we pulled a 4500 lb parts trailer and sometimes we pulled the 1000 gallon fuel trailer behind that, though the fuel trailer was mostly empty in this situation. When the rig was stopped in the field it couldn't hardly pull itself out of the hole but on the road I felt it had reasonable acceleration for the load it was pulling. I kept track of the mileage for 2000 miles and it was an honest 15 without stretching it. The cummins was in a service truck that pulled about the same load but it could easily grunt itself out of any situation it was put into. On the road it didn't have as much acceleration as the Duramax and I wasn't involved with it enough to know what the mileage was. To sum up this long story, it depends on how you use it. If you are grunting a lot of heavy loads for a long time, the Cummins is probably the way to go. If you pull your loads mostly on the highway or maybe if you don't pull any load at all but you like great acceleration on the road and decent mileage, and you trade often then maybe the Duramax is the answer. I wish I knew more about the powerstroke. Just my long winded 2c worth!
