My understanding of this alternative- and someone correct me if I am wrong here- is that, while it does burn cleaner in a vehicle than gasoline, it also burns much faster and is therefore more expensive in the long run. More importantly, the process of "refining" it puts more pollutants into the air than does the internal combustion engine with gasoline.
UPDATE: This is the way of the future, but it is not a good way. We have more and more farmers now dumping soy bean and other crops in favor of corn- because that is where the money is. When the price of corn goes up, the price of virtually everything will go up. This will benefit ADM, not the American people.