The best oil is the oil you can get the easiest, and for least amount of money (and of course meets specifications)

OEM's don't make oil. They just put it in a pretty bottle.

I usually go with the cheapest brand name that meets my specs. I usually don’t go with no name brands except for Kirkland at Costco. 

I’ve used Pennzoil, Castrol, Quaker State, Valvoline, and Mobil1 in my cars. All were great!  Prius at 290K miles. Accord at 270K miles. Regular oil changes and top offs. 

FWIW, my BMW had a oil cap that said Castrol on it, hinting to use it in that engine. And I’ve used other brands just fine. 

Chances are others have asked a similar question.  A quick search on this forum reveals your answers:

https://carkiller.com/scottykilmer/qa/oil-brands/#post-14357

https://carkiller.com/scottykilmer/qa/oil-questions/#post-17222

Only Mobil 1 Full Synthetic for me. But that is personal preference.

At this point, every company is capable of putting out a good oil. Heck, even Kendall is still around. I say go with whatever is cheapest and fits your requirements. The one thing I would advise against is using bulk oil. This is recycled oil that quick lube places will typically use. I've seen it where the oil was contaminated with coolant, brake fluid, and many other things you don't want flowing through your motor.

Stick to anything in a bottle and you are ok.

As long as you change your oil and filter every 5000 miles any decent oil should do. 

I personally love Liqui Moly. They're quality is awesome. That's what oil price is about anyways...quality. 

But if you don't really care about the brand, then just use any oil that has the correct API rating and viscosity specified in the owner's manual.