http://www.fordraptorforum.com/f5/octane-rating-vs-fuel-consumption-38962/
My opinion:
Anything I've read that's pro-ethanol has always been written by the corn lobby.
Most articles are basically 'meh'.
1. Science says there's less energy in ethanol.
2. Engineering says the only way to get that power back is with greater compression; i.e., the engine has to be designed for it.
3. Engines are rarely designed for it.
There's a possibility - if Ford has gotten sophisticated with their algorithms - that they can adjust timing and turbo pressure to make ethanol worthwhile. Saab used to do it. But my understanding is that Saab's tech has yet to be reverse engineered well enough by anyone to make it work.
So in the end, you'd do it for cost. And the only reason the cost works is because the fuel is 50% subsidized by the government. If you're into government handouts then I guess you're into ethanol.