High quality: WTI is considered a "light-weight sweet" crude oil, which happens to be much easier to refine, though Brent is a mixture of crude oils, which include both equally "gentle sweet" and "large bitter" grades. Screening is by references that POs request each other for, not by released evaluations https://iseodirectory.com/listings13222985/the-fact-about-outcall-massage-that-no-one-is-suggesting