Lots of folks say Amsoil is WAY more expensive than Mobil1. (And even I was almost convinced - so I shop Walmart, etc....) Sometimes Amsoil is less expensive!!! (not "on sale" Mobil1 10W-30, vs. preferred customer price Amsoil 10W-30)

As for the original question. As a rule, true synthetic, done right, is always a better motor oil than the best petroleum motor oil. But, as to how good cheapie "synthetics" are, that's a whole different topic. Since the Castrol case, the word synthetic has become very diluted, to the point that even Mobil1 will cut corners. I stick with what I know, Amsoil of course, and this is a company no matter how ineffecient, how crappy our marketing is and how shitty us dealers are treated, doesn't compromise the product quality.
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