Over the last 3 years, I've gotten 2 bad tanks of gas, both from the same gas station. Scooter idled horribly and power was way down. It's easy to notice low power on a Honda Metropolitan.
It happened to be the same gas station that we always use for our car since we get fuel rewards through the grocery store. Wasn't caused by sitting as we use the scooter regularly year round.
This is in Colorado and we do have 10% ethanol in our gas. There is a station about 5 miles from us that does not use ethanol, but I don't think the ethanol is the issue.
Based on the 2 bad tanks, we've started getting gas for our car somewhere else. Doesn't really help to save ten cents a gallon if the car runs poorly.
Having said that, I think that our scooters will run on any gas in the country, but there are cases where the gas somehow is bad and affects performance.