I have used a wide variety of oils. Motor oil, used motor oil, cheap bar oil, and premium bar oil, the whole nine yards. I use stihl oil now becasue the way i see it, I'm at the stihl dealer fairly often. For things like chains, bars, saws, parts, and so on. Its convienient for me to grab a bunch of what is right in front of me than to make seperate trips, burning gas and time, to go to wal-mart to save a few bucks. I have nothing against wal-mart oil, its just a matter of whats easier for me.
Chris