I have done a lot of research and I have figured out that the maintenance and quality of fuel is the biggest thing with diesels. Correct me if I'm wrong. I have always ran Mobil 1 extended performance synthetic in my truck now and change the oil with the DIC reminder so the oil changes were on the expensive side for me anyway.
With pulling hills I learned real quick that I don't try to pass anybody on a hill. When I first started pulling I was going down the interstate and tried to pass a tractor trailer going up a hill and it didn't work too well. I also learned that I needed to gain speed on the downhill to be able to get up the other side without the truck gearing down and the motor screaming like it is about to come apart.
I have always been a Chevy guy so I was looking for a Duramax. I have researched the Dodge/Ram and have seen some good reliability out of them besides the weaker transmissions in the early 2000's. I know to stay away from the Fords.