I did a little test in my car. I checked my mpg using Super Unleaded containing 10% ethanol and Regular Unleaded respectively; as I expected the ethanol reduced the miles per gallon.
Where I live, fueling with the ethanol blend will save you money per fill-up but not in the long run once you figure your mileage.
Try it yourself. As always, your mileage may very.
Of course if the price is close you can do the math. You will get approximately 3% worse mileage with the 10% ethanol blend.