Blackstone did a big oil test this year and Royal Purple had slightly worse ratings than many other oils. Although the slight variation in metal content will likely never make a difference, you're paying extra for a pretty purple bottle:
https://gallery.mailchimp.com/f64139...Aug_17_ENG.pdf
Consider saving money and using different oil, like Castrol Edge:
http://amzn.to/2gJfBTV