Same here. My 2 chainsaws have been running it unmodified for almost 5 years (obvious carb mixture adjustments) I also run it in my push mower, and my cars (also not designed for e85 - no fuel system changes needed whatsoever, just a tune). It is a fine fuel. I have NEVER encountered any damage from the fuel. Any plastics or rubber lines breaking down are just crappy parts. Plastic holds it just fine in liquor stores...
The only legit place it will cause damage is in boats with fiberglass tanks - that is real issue caused by the fuel.
If your equipment won't run on E10, it is NOT the fuel. You have another problem. On an unmodified engine you can blend in about 30% ethanol before it gets too lean to run safely, and will start showing signs of power loss without jetting / mixture adjustments. That is a rough estimate as every engine is tuned differently, some are already too lean for gasoline straight from the factory so they won't take as much, others are too rich and can take a higher blends.