Depends on who you ask, but most mechanics now say "yes." This is one of those great debates where you can get any "expert" advice you want to hear.
Some---it used to be a majority, but not any more---say E-10 can be bad for your engine; all the major car manufacturers say it's safe; and farmers/corn industry advocates and a handful of mechanics (though none I've talked to personally) say it's actually better for your car than regular gas.
Whatever. One thing I can tell you first-hand is that using E-10 WILL reduce your gas mileage/fuel economy. I found out the hard way; never paid attention to the sticker at the gas pumps at the station where I used to fill up.
In search of an answer to why my '04 Malibu Classic did not get anywhere near EPA sticker fuel economy, I booked up on ethanol and started filling up at a station that sells non-E-10 regular gasoline. Immediately I noticed an increase of about 4.5% (or about 1.1 to 1.2 mpg) in gas mileage.
Not a huge difference, but it's there---and it holds true for all vehicles, from what I've read online. It has to do with the chemical composition of ethanol vs. gasoline; I'll let someone with more scientific knowledge than I explain it.
That's why I never buy E-10 or any form of ethanol if I can help it. The alleged increased air quality/reduced emissions are countered by the increased use of fuel, so I'm not sure how much "greener" it is in the long run. Also it costs more....
I like the idea of supporting the U.S. corn industry and other domestic suppliers of ethanol; I also like the idea of helping the environment. When the scientific geniuses find a way to mix ethanol into gasoline without reducing fuel economy and hitting me in the wallet I will sign on in support.
Till then I am strictly a gasoline guy.
Regards, Eric M