I'm not so sure about the mileage being better on the new truck. My 6.7 averaged between 15 and 18 calculated by hand, with the best being 20 on a trip between Spearfish, SD and Williston ND. My 7.3 usually gets about 16 to 20 with the best being 22 on a trip from Denver to Alamosa.
My $45k 6.7 was a great truck, I just haven't found anything it would do that my $10k 7.3 won't do besides be a little more comfortable and have 2x more expensive insurance and 10x more expensive registration.
just got thru reading this thread and "ttravis5446" has sum'd it up nicely not to mention way early in the thread
my 2002 F-350 7.3 auto double cab 8' bed unit now has over 360k miles and it has never failed to bring me home though some homecomings took a bit longer than planned(same day though)
all the usual wear out items have been rebuilt or replaced along the way butt the expensive ones didn't pop up until i was beyond the making payments stage(alternator, starter, tranny cooler, tranny, 3 injectors, high pressure o-rings in the gallery, fuel lift pump & sock in the tank, water pump, hoses n belt... and the ever needy tires)
my friend who bought a new one like mine brought home a unit w/ a $67k window sticker
it really does have better ride and is noticeably more powerful butt the fuel consumption is about the same except when we hook onto the chuck wagon trailer (high windage and full of cast iron ) LOADED
his drops below 10mpg while mine still gets around 11mpg(¿ did i say the trailer was LOADED ?)
still not a tie breaker...
since mine was paid off repairs have run to the tune of 3-5 truck(mine not my friend's) payments/year mostly in the 3 range which is a tie breaker for me
if i only use SIMPLE arithmatic a $67k loan over 10 years is $6700/year plus interest and taxes... a no brainer
the year i had to replace the tranny was a 6 payment year
i'm guessing the clincher for me n mine is that when my bridal unit of over 50 years and i travel (even when not towing a 30'± trailer) she specifies going in the F-350(not the Jeep Cherokee or her Honda Accord)
we've been from absodadgumlute sea level to up n over The Divide between Lake City and Ouray(several times) in that beast and it has brought us back to lunch @ Handlebars in Silverton safely each time
every vehicle has it's purpose and abilities and the infamous 7.3 F-350 sure has it's place in my heart