High-quality: WTI is taken into account a "light-weight sweet" crude oil, which happens to be simpler to refine, though Brent is a mixture of crude oils, including both "light sweet" and "heavy bitter" grades. Screening is by references that POs request one another for, not by released reviews or from https://maps.app.goo.gl/VhAGTRCDGTuVhHJa8