Brand name oil
It is a little bit different since generic meds have the same active ingredient. I would consider all ingredients in motor oil to be "active" and they vary from brand to brand.
Generic. My wife and most physicians I know have no issue in prescribing them, so I have no issue taking them. For OTC stuff, you better believe it. Although, I am a bit conflicted when buying private label stuff. The retailers have a much higher profit margin on that stuff, from what I've read.
I'm on 3 different medications that I have to take on a regular basis for the ailments I have (not serious), and would cost me a small fortune if I had to pay for them. Problem is that my Health Benefits from work will only pay for the "Generic" version if one exists and if there is no conflict with using it versus the "Real Thing"
I haven't had any problems with "Generic" drugs because I think there is more controls in place than you would have with a Motor Oil.
After all... Engines can be replaced, we can't!
I go generic on OTC and prescription. I even found something to replace Lipitor (no generic Lipitor available)but there are generics of other medications that do the same thing.
My test results are as good as with the Brand Names.