150K miles for a diesel is just getting broken in. Mine only has 100K with only minor problems so far. And I've heard only minor problems being reported by other owners. There was a spate of fuel system problem reports a couple years ago but It was never clear to me just how common those were. A few very PO'd owners can make a lot of noise. And I have seen no reports like that for quite awhile now. No doubt those were expensive fixes but other than that the trucks are quite reliable.
Of course any complex manufactured product with have occasional lemons off the manufacturing line.
However, I could be wrong here, but I thought the extra weight of the diesel engine reduced the truck's carry capacity. Which is based on the suspension after all. And if you are worried about carrying something heavy in the truck bed then payload is what you need to be concerned with. You would be better off getting a one ton rather than the 3/4 you are looking at.
