Please let me clarify why I would not buy my 2007 5. 9L if I had to do it over
The noise level is much lower in the '07 and the brakes are better due to the disc rear, other than that I don't think there is much improvement. In fact, I think that with all the electronics and common rail injection, reliability is reduced and maintainance cost are going to be much higher and more frequent as the miles increase. What's more is the ability to work on your own truck is greatly reduced due to the increase in technology and the very, very expensive maintainance test/calibration and programming tools, along with the high price of injectors,ECM's etc. Even the light systems on my truck is computer controlled. Of course this is true for just about any new vehicle.
I don't think that a person that trades in every year or every three to five years would have to consider the above argument. The same as one that trades in with at or less than 100K miles.
For myself, I would have been money and reliability ahead to find a good used 12 valve or earlier 24valve 4WD and correcting the main problem/s with that particular year... . Avoiding the 53 block completely.
By the way with so much glass in the new truck it is like a greenhouse inside at 65 OAT it is pretty warm in the cab.
YMMV