Ethanol sort of is both good and bad, unfortunately mostly bad.I've always run the hi-test in all my bikes. I tried the regular grade but they pinged with it. The new alcohol laced gas seems to work OK in the 650s but I try to get the no-alcohol fuel whenever I can. The bike seems to like it a little better.
The good thing is that pure ethanol actually has a higher RON/ MON rating than even premium EO pump gasoline (race gas/ avgas is another story) In fact, "flex fuel" turbo charged cars give more HP on E85 than on even 99 RON V-Power.
The main bad side is that ethanol causes corrosion, damaging plastic and rubber components, and being hygroscopic. The other negative is mainly affecting carburetted engines, as they run lean when using ethanol mix. However this should be pretty easy to fix with some carb jetting/ fine tuning. Fuel injected engines with a lambda probe will automatically correct fuelling, so no issue there.