The only way to know for sure would be to test both. I suspect that cars run exclusively on E0 would last longer, function better, and get better gas mileage as you said. Almost all the gas in Texas, at least where I live, is E10. The EPA wants to go E15. Probably not a good idea either.
Ethanol is most just a stimulus plan for farmers and environmentalists. Again, IMHO.
I’m not arguing the politics, I just don’t believe the FReepers who continually yell “ethanol destroys engines”.
I have a barn full of old stuff that has run on E10 for 20+ years.