My buddy just bought one as his work truck. He was coming from a 4.7l V8 Dodge Dakota.
He LOVES the truck. Uses it to tow a 16' enclosed work trailer that probably weighs around 4000 pounds depending on what is in it. He told me that the power was "significantly better" than the Dakota, and he is very happy with the MPG.
2012 RAM 3500 Laramie Longhorn DRW CC 4x4 Max Tow, Cummins HO, 60 gallon RDS aux fuel tank, Reese 18k Elite hitch
2003 Dodge Ram 3500 QC SB 4x4 Cummins HO NV5600 with Smarty JR, Jacobs EB (sold)
2002 Gulf Stream Sea Hawk 29FRB with Honda EV6010