My only comment is, they are all good and your decision should be predicated on your wallet. Personally, I own both Stihl and Echo and both are fine. I also own a Echo brush trimmer, also good. I only run syn gas in my stuff, Echo Red Armor 50-1 because they don't get used frequently and the syn gas won't give you carb issue if it sits. In fact the Echo Red Armor is good for 2 years of sitting.
I read a lot of whining about the Stihl M-Tronic saws but I don't own one. All my Stihl's are pretty ancient as in 40 years old plus but still run fine.
The key to any saw is keeping the loop sharp and using good bar oil plus in my case syn gas.
Chainsaws aren't built for making sawdust, they are built for making wood chips.
I blow mine off after every use as well. People that let them crud up, restrict the cooling and an overheated 2 stroke is on borrowed time.
They are all good. Let your wallet be your guide and keep the chain sharp.
As an aside, I work part time for an Echo / Cub Cadet / Kubota dealer and most of the saws we get in, they were either straight gassed or so filthy the engine got overheated and seized up to a lesser extent, whining customers complain their saw won't cut.. A dull chain will never cut. Learn how to set a chain and set the rakers correctly. I machine grind all my chains and store customers as well but proper hand filing is just as good for you with one or two loops.
