I began listening to a Florida Amsoil dealer, Dan Watson, who claims to be a certified lubrication specialist and an Amsoil dealer for over 25 years. He has done many videos and radio talk shows explaining the merits of Amsoil products, and genuinely seems to know a lot about the topic of lubrication.
Anyway, one of the big takeaways for me is that Dan has explained that, concerning synthetic engine oils, most brands are "full" synthetic, whereas Amsoil engine oils are "100%" synthetic. The difference being that "full" synthetic oil uses synthetic only for the base oil; the additive carrier oil is likely to not be synthetic for economy sake. Amsoil engine oils are the same type of synthetic for both the base and carrier oils. The term "full synthetic" would obviously lead most people to believe that it means 100% synthetic, but, the terminology is allowed to be used for these "not completely synthetic oils".
Also, when it comes to Group III oils, there can be various levels of Hydrocraking in its production, leading to various levels of the resultant performance of the end product. Amsoil Group III oils (Not Signature Series), are all made using severe hydrocracking, resulting in top performance for the group III category. Other brands may use only hydrotreated (a less processed oil) oils, and even then, only in the base oil - not the additive carrier oil - and can still legally say they are "full synthetic". Guess this may explain why some "full synthetic" oils have such an attractive price.
After learning this and using the product for the past several years, doing some UOA's and even some VOA's, I've come to be satisfied that Amsoil is a consistent good quality product. Sure, I could save a few dollars in the short term on some cheaper brands, but having my engines, that are worth thousands of dollars to replace, properly lubricated is peace of mind to me.
Hope this is helpful to some out there.....thoughts?