10% ethanol has been common for many years in the midwest (where I grew up) the ethanol blend will do no damage to the engine, and is authorized under all major manufacturers warranty terms. Many actually encourage it.
A few benefits of ethanol gas is that it burns cleaner and it also absorbs all water that forms in your tank over time. This is VERY beneficial to people that live on cold climates due to the fact that you no longer need to run isopropol alcohol (HEET) in your tank during the winter months. You will notice on average a 1 MPG decrease in economy until the ethanol cleans the water and other contaminiates out of your system. once its clean, you will return to normal, or 1 MPG better.
Also ethanol reduces our dependancy on foreign oil, it does this by creating 34% more energy than it takes to produce it. It also helps out the US farm industry by making a VERY large market for their crops.
One MAJOR risk of this fuel is that it CANNOT be used with a two-stroke engine. The reason is that the ethanol that is dissolved in the fuel will not properly mix with the oil, thereby stopping proper lubrication of the engine.
See
http://en.wikipedia.org/wiki/Ethanol#As_a_fuel
Or you can see this link as well
http://en.wikipedia.org/wiki/Ethanol