The glider club's quad-cycle generally runs on 100LL, seems to like it.
True about "mogas", or unleaded hi-octane fuel, being suitable for many older aircraft engines, but in the US at least, three's so much doggone alcohol in it that it's unwise to use it. It can dry out seal and rubber fuel lines, etc over time, and it can also increase the chance of contamination, because alcohol in gasoline can actually hold water in suspension(?) in the fuel so it can't be detected by the usual sump-sample method. If your engine gets a swallow of fuel that's mostly water, it could stop on you... and
not at a convenient time!

That being said, though- some pilots go thru the hassle of analyzing and treating mogas samples to eliminate the alcohol, or they'll just make sure they have a good mix of mogas and avgas, which seems to minimize the risks.