MTBE is horrible for the environment, I forget why, but I think it gets into ground water really easy and can cause birth defects and shit like that. Where as, ethonal is completely renewable, and supports farmers. On top of that ethonal is extremely good at raising octane levels. I used to run E85(85% ethonal) in my Ford Ranger 3.0L and it was rated between 103 and 115 octane(boost friendly

), unfortunatly it is extremly corrosive and e85 can only be run in certain vehicles (ford and chevy 3.0Ls among them) but once car makers start to take adjust to this it won't be a problem. Also, once it has more widespread use, the price will go down. So it will be cheaper , better for performance, renewable and more environmentally friendly...all around a good thing.