I lean towards using full synthetic ester 2T oils for several reasons. They are polar, they offer greater shear value, they can be formulated to combust at the right temperature, and they can be formulated to burn cleaner. For these reasons I believe that they will give me better long term protection, which for me is the most important factor.
That being said, I believe there are many synthetic blends that can provide yeoman service to the vast majority of users. We are uber fanatical here, but I think the vast majority of users would not notice the difference. The problem with synthetic blends is that the base stock can be any mixture, and since the Castrol suit, highly refined mineral oils can be classified as synthetic ( another reason I focused on full synthetic esters ).
Between the equipment manufacturers, the oil producers, and the independent oil raters, I would suspect that there has been tens of thousands of hours of research done on this subject. And is continuing to be done. By chemists and engineers that have spent their careers immersed in this subject. I suspect that the research done by manufacturers that is made available is filtered through marketing. And EPA mandates. I would think that the engineering divisions of any of the oil producers and bottlers would know how to produce an oil that is suitable to the particular demand. The producers of oil formulate oils to a price point. They also produce "boutique" oils that are probably cutting edge. Whether or not it is worth it to you is your decision.
Again, application is everything.
