I don't trust ratings/reviews on complicated products/subjects like that. The vast majority of buyers couldn't tell you anything about that oil beyond the fact that it's purple. If they do say something about it, it's usually a regurgitation of the marketing on the label. It's likely 4.9/5.0 customers have never done a UOA, never pulled their valve cover, never cut open a filter, or done really anything beyond changing the oil and checking the dipstick, much less established any sort of trend over several intervals. They realistically have no way of knowing how well it's actually performing and are just letting the placebo effect come through in their review. "It's F'ing purple, yo! 5 stars!"