High-quality: WTI is taken into account a "gentle sweet" crude oil, that's easier to refine, whilst Brent is often a combination of crude oils, like both equally "gentle sweet" and "weighty sour" grades. Screening is by references that POs ask one another for, not by published testimonials or from other https://maps.app.goo.gl/VhAGTRCDGTuVhHJa8