I ALWAYS recommend E FREE, however, if you use the machine at least, weekly and properly store it in the winter (tank drained and carb ran dry, on carbed models of course) Ethanol will be fine... I use StarTron in all my equipment and repairs and have no ethanol issues in the last 3 or 4 years.
i do NOT recommend Sta-Bil, as it has a tendency to fall out of suspension in the gasoline,and cover up and gel everything over with a pink varnish. even in fresh gas. i see it about 5-6 times for every 40 carbs i work on, i'd say.