Its all personal taste. I myself run Schaeffer's oil in my Mazda6, and Amsoil in my turbo cars. My basic work/daily gets whatever is on sale at the time. And has gone 300k on that garbage oil. So that says alot also. Really just buying the correct weight oil is more important then brand alot of the times.

 

Mobile one oil thins out more then others when it comes to temp. Oil was sent to some facility for testing because it seemed like a lot of Subaru motors were wrecking rod bearings and came to find out 90% of people were running mobile one. Other 10% were people that just let oil level drop too low it seemed. o steer clear of mobile. I myself use castrol or Valvoline now and no issues on Subaru, a Pontiac, and my picky 86 rx7 w a rotary engine.

 

I put 5w 20 what's recommended by the manufacture for my 2003 6i. The brand I use is Castrol . Always conventional and engine runs strong as ever with 175000 miles.