I haven't seen any issues with my gas tractors as a result of ethanol. I shut off the fuel on all of them as soon as I turn it off, so it may cause the needle to leak and I don't know it.
Smaller things with "rubber" fuel lines are a nightmare because of that stuff. I think it is a combination of things being built cheap and the ethanol, but those rubber lines and primer bulbs on trimmers and blowers last about 9 months.
I do know that gas smells more like a skunk than the fuel we had when I was a kid.