I used E10 up until I purchased the 441. My Echo blower I just got back from the dealer after dropping it off for carb adjustment said it was mostly due to the screen getting clogged by E10....and they adjusted the carb.
My biggest beef with all this "use non-ethanol" crap is that if it's not covered under warranty, then why the hell say in the manual that it's okay to use E10?!
Anyway, now that I have a place within 5 miles to buy non-ethanol (91 octane), I guess I have no more excuses for not buying it. But still...it's the principle that counts.
Well, think about it, they really have no choice. 99% of the pumps out there, all they have is e10. They can try and make the materials withstand it better, but...if it isn't fresh and stored incorrectly, etc, the owner yanking on a tank of sludge is gonna get what he paid for, sludge.
The saws will run fine on e10, it is when it sits and phase separates, then it is trying to run on like 50% water/ 50% alcohol, which will be first sucked up the tube from the bottom.
I know my local shop starting saving all the fuel from the tanks to show the owners if they want to complain about repairs that are related to improper fuel. They said dudes were just constantly arguing with them and that worked. It's in the manuals, on company websites, etc fresh only, not old, and stored properly. A month or three or six old, in some old can without a cap, fulla water moisture, and guys wonder why their gear doesn't start or why it toasted. Got their sludge in a glass jar, you can show them. Pull the sludge straight outta their saw/trimmer/mower, pretty obvious why it is not so hot especially for casual infrequent users and guys who are just cheapskates and buy the cheapest stuff they can find.
And even if the pump says e10, various independent tests around, some reported here, can show as high as e20 from the pump!