I simply am not a fan of Ford's modular motors although the 6.2 is one of the better from the Ford terd modular family but it is still far from stellar.
The Ford 6.2L isn’t a modular engine, it’s nearly completely different than the Tritons. I addressed this, in an earlier post. What makes the 6.2L far from stellar?
Less impressed with GM's new 6.6 gasser but time will tell the tale, and so far none of the others yet match the GM 6.0 legacy of reliability.
What are you not impressed with, from the GM 6.6L gas?
No engine will have better legacy of reliability, than the old GM 6.0L. Some may get as good as, but I seriously doubt anyone makes as many engines, in as many trucks, with as few issues.
Gas mileage on any of them is not going to be good. Fuelly website pretty much shows the ole 6.0 is no worse than motors decades newer than it. Now some people seem to feel better if their lie o meter in the dash spits out a number 2 or 3 mpg higher than they are actually getting but fuelly website usually proves they are not really getting that lie o meter number they think they are getting either.
My fuel computer is often right on. I hand calculate every tank and keep records in an Excel spreadsheet, for both of my vehicles. Sometimes it is a few off. My fuel “lie-o-meter” only gives to tenths. While I calculate to hundredths. It’s within a rounding error nine times out of ten. When it is off, it’s off by 2-4 MPG. Much better than my Silverado. It was correct, sometimes, but was usually off at least 2-3 MPG.
You are correct in that fuel mileage will not be very high, with any of the big gas engines. High single digits to mid-low double digits, depending on application.