There was a post by a petrochemical engineer going round not long ago and he reckoned these so called fuel stabilisers don't do anything.
Fundamentally the problem with ethanol is that it's hygroscopic (absorbs water) if left standing. So while modern engines might run OK on the stuff if you leave it in the tank for a length of time it could absorb enough water from the atmosphere to cause corrosion problems in the tank and fuel system. The E5 we've been using for years seems to be *just about* OK but the new E10 has gone across the line into "bad fuel". If you're only going to lay the bike up for a few months and it's in a dry, heated garage you probably won't have any problems. For longer term storage you need to get the E10 out of your system, preferably in favour of something that has zero ethanol. Some premium brands of fuel are still ethanol free but I use Aspen petrol, which is an alkylate fuel designed for garden machinery that commonly doesn't get used for months at a time. It's very stable, if it evaporates it does so cleanly, and it's perfect for keeping your tank and fuel system clean. Only disadvantage is it's expensive at £4/litre, so I drain the tank, put a couple of litres of Aspen in, run it for a few minutes and that's job done for the winter.