Funny, I talked with my dad this afternoon and he puts almost any oil in his cars and he has a background in the auto industry. He just retired after 36 years of service in the Cleveland Casting Plant. He would buy whatever case of oil was on sale at the local auto parts store. In my old Escort he used to use Valvoline, but in his cars he would use Shell or Quaker State.
I used to use Penzoil because that is what the lube shops around here typically use, but I got a coupon for $15 off at Valvoline because I hadn't been there in a while. It really helped because a regular 5w-20 oil change at 7.75% tax would have come to nearly $36. I almost **** myself. I couldn't believe it. Anyway, I noticed right after I pulled away the difference. My vehicle's RPM's seemed lower and the engine purred like a cat. I get an oil change around 3,300 miles. I'm sold.