The problem with ethanol isn't environmental, but comes when the engine is stored for an extended time. Things get all gummed up and the gum is difficult, if not impossible to get rid of. In order to avoid that issue, I have switched, as much as I can, to non-ethanol gas. Unfortunately, it is not always available, so in the last tankful before storage, I now use Sea Foam. Not a perfect solution either, but better than sacrificing the engine to ethanol induced gummy failures.
In my car that the owner's manual says "use regular gas", I did a 1500 mile each leg experiment with regular (E-10) and premium (E-0). for less than 10% higher cost for premium, I got more than a 10% improvement in economy. I won't go back to regular.