I forget which one whether it's ethyl or methyl but one will attack the rubber in your fuel lines. Also, alcohol has less thermal energy so you burn more.
Here in California, alomst every pump says it's possible that the gas you're buying may have alcohol in it.
I'm all for something that limits our dependence on foreign oil. Right after we use up the rest of the world's supply.
Must be methyl. They are already using fuel lines and seals that are designed to be resistant to ethanol. I also recall that in the 40s and 50s scientists conducting rocket experiments that used methyl as a fuel component ran into some similar problems.