The past tests have shown a slight edge given to Royal Purple and Redline over Mobil 1, but certainly not enough to pay the high prices that Royal Purple and Redline charges. You can also get Mobil 1 at any Walmart store that has car stuff. I ran Royal Purple for a few years, but then changed to Mobil 1 and and have seen no difference in the amount of miles I can drive without an oil change. I guess if you race your car, Royal Purple might give you an edge, but I don't know why.