I work for petrocanada and can tell you that the only difference between petro, sunoco, esso and shell is the additives that they put in the fuel. All supreme fuel from all companies has no ethanol in them. Ethanol isn't bad for engines. The only problem with ethanol is that its corrosive when mixed with water. When people started using gas with increased ethanol it simply cleaned there tanks out and this caused problems with there motors. Ethanol has been in fuel for a number of years they have just increased the amount of ethanol in the fuel.
Cheers Jeff