We have been running the 4 mix hard at work. Only issue at first the conventional oil. Read a post here saying use synthetic like hp ultra, in fact think if I remember right they are made to run on it. Only had to adjust valves a time or two, but so far rock solid. I am sold in a pole saw form. Trust me though the 101 is tried and true, the less weight is really noticeable. Still have great power. I try and explain to people, even though I am falling trees and cutting stuff as big as 18inches and up, at some point you will have to use a bucket truck, or climb and get up with a chainsaw. The power of today's pole saw's is not an issue. But weight can be fully extended. Just trying running it day in, and out. It is very different then a chainsaw right in front of you. And the 101 is tried and true. We are still having some minor issues with the 131. Just my thought's Oldiron.