I used Valvoline and Maxlife for years, and now I use Napa brand conventional which is nearly identical to Valvoline branded oil. Never had any problems at all with any of them except that I got a little less MPG on Maxlife. I stocked up on a case of Napa 10W30 and a case of Napa 5W20 for my truck and gf's car when it was $1.99/qt.
I am thinking of changing over to Mobil Clean 5000 though. Saw it at Walmart yesterday, $2.37/qt. I think it would be good to use a good robust dino like MC 5000 for that price instead of paying a higher price for Valvoline or even Napa brand oil. I'll still use Napa ProSelect filters though. That's the best filter I have found in a normal $3.00 price range. Never had any problems with them.