Once I had to rent for a 300mi one-way trip.
They gave me a Tahoe because they were out of Versa's.
It had the typical 5.3l V8 and CD with some kind of dash indicator.
The trip was thru remote parts of CO and NM , a route w/ 50mph rough roads that I could achieve over 40mpg in something like my cx5.
I watched the dash and found that around 50mph it would show 28mpg if it was in 4cyl mode but if I just touched the gas slightly it would drop to 22mpg (at 50mph).
It would show 18-19mpg on the interstate but as most of the trip was on secondary roads it showed a reasonable number for the entire trip, considering it had a v8.
I didn't think the overall experience was much better than my cx5. True there is a bit more room around the seats, etc., but I think people that think big cars are way superior should try a modern 4cyl.