I drive a 03 f350 v 10 and let me tell u that thing has more balls than i have found a use for. With that being said ive heard a lot of good about the new 6.7. We have four of them at my work and so far they have been the most problem free (compared to a 14 cummins and several 14 and newer duramax).
I used to have a 97 7.3 when i was in high school and when i got my v10 i noticed almost no difference in mpg or power wven compared to my dads 01 7.3
I prefer having a gas motor now becuase parts tend to be a little cheaper and it isnt nearly as easy to tear apart and build.
Fords newer 6.2 is a good motor as well. My brother has one and its really a nice truck. He pulls a 32' bumper pull camper with his and he says he never really notices it bact there until we hit the bigger hills... another thing to keep in mind is that the difference on the interior of almost anything new is drastically changed. When my lariat came out in 03 it was top of the line. Now to find one as basic as mine is almost impossible. Not sure if you are into all that tech stuff but i know im not as its more that can go wrong...