Like others have said, there is a difference between a vehicle that requires premium vs one that recommends it for best towing performance. I’ve had both.
We currently have a 3.5 EB in a 2019 Exp MAX. I’ve used both regular and premium in it. It usually gets just regular unless I am towing over the Rockies. I haven’t noticed any difference in MPG with the two fuels.
I do think that you comparing your old 5.3 in the Rainer vs the current generations 2.7 isn’t a fair comparison. While i haven’t checked fuelly, my guess is the current 5.3 gets significantly better MPG than yours does, and probably isn’t at a deficit to the 2.7 if you are comparing similar vehicles.
Speaking of similar vehicles, you aren’t really comparing that. The Tahoe you have looked at would be a direct competitor of the regular Expedition.
Have you looked at the Hyundai Palisade or the Kia Telluride? Personally, I’d probably look at those more than a Edge.
One final note. You should look at a Hertz dealership (associated with the car rental agency). Because of the virus, they are off loading a lot of Edge and Tahoe’s (and similar vehicles) due to the virus. As a general rule, those vehicles will be very low mileage and have been maintained to manufacturers specs. Honestly now might be the best time to buy something like that.
