I use a name brand, Stihl, Husqvarna, Echo, Stamix, etc...
Because they work fine, and see no real need to get anal about such
trivial concerns. Saw failures are caused by dirt ingestion, lean seizures,etc..
Type of mix, octane{for regular to premium in the U.S.}, plug brands,
synthetic vs. dino, and so on, really make for lively discussion, but in reality
have little to do with saw longevity generally. In high performance applications there might be room for arguement.
As far as the chemistry behind the brands I use, I have no idea, as it is
not needed to know.
But this will likely be a long thread, full of rythmic swells of passion.