Only Stihl's i own. Bought a 600 and a km110r back in the mid 2000's or so and used for 10 years commercial use only problems with trimmer was a few throttle cables. Not one problem with blower that I still use almost daily to blow sawdust offen sawmill at the end of the Day.(might take 2 minutes).It only gets warmed up twice a year doing yard work or when burning a brush pile. Adjusted valves In trimmer I think once. At the time of purchase I had a jonsered trimmer that i wasn't happy with for the application. Just my experience with the 4mix.