Buster not all esters, and PAO's are created equally. Some ester are functional worthless as a lubricant and are just their for solventcy issues with additive package, some esters are prone to absorb water while some have the ability to resist high temps, shearing and boiloff. The same holds true for PAO's. SOme company use as many as six different synthetic base stocks to blend the oil in the bottle. Seldom does one base stock alone have all the propertys needed for an application! I think the reason people give M1 a little bit of grief is 5 fold. 1) Mobile 1 has been in the game long enough to know how to build the best oil but they choose not too. 2) They have the resources to change the chocked oil system (API) in the USA but are afraid to! 3) They will not stand behind their products capabilitys and choose to stick with the wimpy 3000 mile oil change policy.4) The still will not offer the better European M1 formula in the USA.5) They are the Big Bother and everyone likes to hate a Big Brother in any segment.