In my experience... (Score 1)

I used to work for several auto dealerships in the past. As a general rule E85 certified vehicles were always rated to get better mileage on gas than on ethanol. As for vehicles being damaged by ethanol I remember in particular that fuel pumps were one of the biggest problems we faced with vehicles that were not E85 rated but were running on what the gas stations were selling at the time(a blend of ethanol and gas...not sure of the % though.)