Interesting about the Prius. I have a 2010 Honda Insight at home, which for the time had excellent equipment, and I would assume a 2018 Prius would be far more equipped than my Insight.
But I went back to Avis, and I asked to swap, they didn't have much in the way of cars to give me, but had a VW SUV, which was the next class up. I went to look at it, as soon as I opened it, I could tell this car was going to be great. It had everything I wanted. Went back to the desk, and said I liked that car, they said no problem and upgraded me for free.
I do wish that I had actually just paid a little more when I made the reservation for a Tahoe or Explorer, as they are the best for long distance driving! In terms of comfort, not fuel economy! I've rented 2 Tahoes through National, and they were amazing cars to drive.