Wordmovers,
I found this site to be most useful re: E85.
National Ethanol Vehicle Coalition
The FAQ addresses the mileage issue. I do not run E85 but am looking to. I would take the hit on milage and probably pay around the same as conventional fuel on the basis of reducing emissions, dependence on foreign oil and the nature of a renewable resource. There are some drawbacks, and no perfect solution, but E85 has a lot of pluses. From The FAQ:
Ethanol has less energy content than gasoline. However, E85 also has a much higher octane (ranging from 96 to 105) than gasoline. FFVs are not optimized to E85, so they experience a 10-15% drop in fuel economy. This will vary based on the way one drives, the air pressure in the tires, and additional driving conditions.
