Around here you cannot buy ethanol free gas as of about 3 weeks ago. Pyrofax (I think it's a division of Valero fuels) out of Quebec was the last supplier of ethanol free gas in the area, and they switched to E10 on the first. I work on a fleet, we have our own fuel station. We buy fuel from these guys. We now need to spend more money on special filters and equipment to use the stuff... Ethanol likes to absorb water which is part of the reason why it will crap up a fuel system if you let something sit, and it will do the same to a storage tank.
I noticed an increase in gas mileage using the stuff, the difference was well within the margin of error (.4 mpg) but the increase has been pretty consistent so far so I dunno.