The MPG is not really a big deal, I can handle that. However, pure ethanol attracts water. I'm not sure how much water can be absorbed if its blended with gasoline but either way, it still could be hurting our engines. My car was built early 2006 before ethanol was mainstream and I personally do not think that my engine and fuel lines are optimized for the use of ethanol. I'm not saying that ethanol is going to stop my car in its tracks if I fill my tank with E10, I'm simply thinking long term. No one really knows what the long term effects are. It could hurting the longevity of the engine especially if water is being absorbed into the blend of gas and ethanol Many say there is nothing wrong with ethanol and that may be true if you car was built after it became mainstream.