Unless your car is turbo or a 14-16:1 race motor, forget about E85.
Advantages on a turbo car, besides the higher octane is that it burns so cool, you almost don't need an intercooler. On a 9:1 NA street motor, I can't think of 1 advantage. Even the lower, taxpayer subsidized cost/gallon is lost in the extra volume consumed.
E85 is only cheaper than gasoline, because your grandkids will be paying for it long after you are dead. The government isn't 20 Trillion in debt because it makes wise economic decisions. When Ethanol mandates really took hold, I personally know more than a few corn farmers that went out and bought $120K 2009 ZR1's. One told everyone he Was "going to run 200 mph" in the mile with his. When he only ran 180, he spent another $40K on it until it ran 204 mph in the mile. Super nice guys, but they have always been dirt poor corn farmers... your grandkids will be paying for that 204 mph ZR1.
E85 was also a scam the big 3 used to get one over of the crazy CAFE regulations. Since its only 15% gasoline, a 13 mpg truck that can run E85 can say it gets (100/15 * 13) = 87 miles per gallon of gasoline. Never mind it takes a the equivalent energy of nearly gallon of Diesel to make a gallon of ethanol, words are words and the CAFE std did say miles per gallon of gasoline. Shhh don't tell anybody... Its a secret.
It never made sense that the Turbo cars (like the 2.0L ecotech or the Ford Ecoboost) weren't "flex fuel" but the crappy gas guzzlers WERE flex fuel (so they got EVEN CRAPPIER gas mileage). It all made sense when I found out the scam.