This may not be a popular opinion on this site, but I can say that after using oxygenated fuels for far more than a decade it has had little or no affect on the life or performance of my various toys.
It includes 47 years of boating with 2 stroke outboards (I was on the water today), 40 years of off road riding, 27 years of that were racing in the pro class (still own three bikes) and assorted chainsaws, both new and old.
I've used high octane leaded pump gas in the sixties in my muscle cars, to unleaded regular 10% blend in my boat today.
The facts tell me that I most likely saw a slight reduction in HP with the new fuel and that if I store the fuel in a poor fashion there is more of a "chance" of phase separation, or other problems.
Some time in the late 80s or early 90s when we first started using ethanol here there were plugged fuel filters and carbs in older cars and little used equipment. Plus there were fuel line or system issues because there were so many engines made years early when there was no thought of 10% ethanol blends and they used non resistant products.
Most everything made since the early 90s was designed for use with ethanol blends, meaning rubber parts were at least more resistant to it. Many boaters still complain that the blends destroyed parts in their carbs, and, well, it does. These carbs hadn't been rebuilt since they were made in the 70s and were long over due for a rebuild (new kits come with resistant parts and have for a very long time).
As the trend towards 10% blends throughout the country marches on, each new area targeted starts screaming that it will destroy every piston powered thing they own. The reality is they may see some problems as the ethanol cleans out the fuel system, or if the fuel system is long overdue for a rebuild it may cause fuel lines and other things deteriorate, but for the most part that’s about it.
Don’t get me wrong I don’t like blends and I’d rather they weren’t used, I also think it’s a feel good scam. But to say my life has changed much because of them would be a lie.