I have a BIL with a 16 F150. Mine is a 14, last of the steel bodies. The aluminum isn't causing any issues. It is tougher than steel, but with the same damage does cost more to fix. But with the same type of crash may have LESS damage which could mean less cost overall to repair.

A good video

https://www.youtube.com/watch?v=oDQZu8K51ZY

There is less weight difference than advertised. With a regular cab it is only about 200 lbs. A crew cab less than 500. And that doesn't mean more payload. Most of the steel bodies have 7350 lbs GVWR. The aluminum bodies 7000. So while they weigh less, that rarely means more payload.

All things equal I don't think there is any measurable difference in fuel mileage. Maybe if you take it out to 2-3 decimal places.

I've made 2 road trips from GA to CO in the last year. In November for an elk hunt. My 14 Crew cab 4X4 with 5.0 V8 and 3.55 gears got 17.9 for the round trip. And that included 5 days of grinding up and down mountain roads covered in snow in 4X4 and on winter gas. In June my wife and I took our 11 year old grand daughter on a road trip to see CO. We did a loop around the western 1/2 of the state and up into WY. I got as much as 21 on one tank with 19.3 for almost 4800 miles total. Typical for me is almost exactly the same that Magnum Bob reported above.

And the 36 gal tank is great. Wouldn't want to go back to anything smaller.

Most people don't really want the truth.

They just want constant reassurance that what they believe is the truth.