the main difference between "flex fuel" and regular cars is the plumbing, methanol is corrosive. it's bad enough we're forced (almost) to run 10%, and the idiot in the WH wants to up it to 15%. ethanol actually causes more harm to the environment than gasoline. it also raises the price of food world wide, hurting the poorer countries. the only people who like ethanol in gas are corn farmers, they raise their prices and sell all they can grow.
I am and proud of it, but then here in Canada I cheer for another small market team - Hamilton Tiger Cats and I live in the GTA , which really means Toronto.
As to the debate about which to use, my response is neither. More complicated , more work and more expensive, especially when things go wrong. And there is no such thing as a poor corn farmer anymore - thanks to government interventions. Or is that from lobbying? Hmm.