I now only have one 6.7 diesel, I agree quite a good engine, decent fuel milage
and yes more expense on maintaining. 180 for oil change etc.
My 15 had a def heater go, not covered under drivetrain warranty.
$450 plus 2 hours labour to change, I was told thats the cheap one, there is two.
2nd one part of fuel delivery system and north of 1000 if it goes, I traded at 144,000 it did not go in that time.
That said, I replaced 2011 crew truck with 2019 diesel and I replaced my 2015 diesel with a 2019 gas.
I did the math, with cost of engine, maintenance it was not worth it for what I need.
So my new truck has 6.2 gas another very good engine.
My reasoning, I plow with it, so milage not great but wasn't with diesel either.
Cost more to take care of, and price of upgrade is $10,000
Also price of gas now is often cheaper than diesel.
I also don't haul much in summer, so not working super hard.
Milage to date is about 2km per hundred better in diesel fuel cost more than offset.
I have the savings at $4200 + in 4 years including resale, let you know in 3 years how right I am
Biggest decision would be how much are you hauling with it and how often.
The 6.2 has no issues hauling but likes fuel when its doing it, like similar to plowing snow