Main problem with ethanol in the petrol is that it attacks plastic and rubber components that aren't resistant to it.
But only with old engines that haven't had modern components fitted as part of a rebuild, and not if you put something like Valvemaster and/or Stabil in the fuel.
I lost a carb diaphragm in one of the generators (a cheap Chinese Honda knock-off) some years ago, but since then I just bung in 5mls of Valvemaster/5l fuel and I've had no further trouble in anything.
