I realy have mixed feelings about Amsoil.
As far as I can see, their products get good results in real world field tests and clearly are fine products. Then they keep talking about the 4 ball test which is at best a margional test of an oils performance in the real world. People get turned off because they remember the guy on TV using bleach to outperform all the oils in the 4 ball test. Kind of puts them in the same "bed" as Prolong and Slick 50, and that is a shame.
Why Multi Level Marketing? Just a guess but I suppose some guy came up with a good oil in the 70's and could not get or did not have the capital to a national distribution network, they cost a lot of $$ and it takes years to get your $$ back.
So he goes to a relativly less expensive MLM plan and "boom" he is in business. Maybe it is the only way he could have gotten started but somewhere along the line (maybe after 10 or 15 years) they should have "bought out" the MLM distribution network and gone to retail distribution. Especially after Mobil 1 entered the market and "developed" the market quite aggressivly.
Why does Mobil have maybe 75% to 85% of the synthetic market now? First they make a pretty good oil, they market it well, it is available on the shelves of most any store that sells oils, and it is priced at a premium to conventional oils but generally lower than the boutique oils.
Let's see how this works, I think Mobil 1 is better oil than conventional (marketing), Mobil 1 performs well in my car (pretty good oil), I can get Mobil 1 easily (distribution method), and I can justify the cost because my car deserves more then just conventional oil (marketing & price position).
The reality is that for probably 75% or more of the people currently using a synthetic oil the only thing they really get is the "marketing" benefit.
Engines will run "till the cows come home" with todays conventional oils and a reasonable oil change interval. Engines run under the most severe conditins would benefit from the superior properties of synthetic oils and that ain't many of us.
Just to set the record straight, I run synthetic oils in both of my cars, 5w30 the year around and I am pleased with the value I get. But them my cars are special and deserve better than average care (I think the marketing got to me).