Mentioning motor oil in another of the automotive mailing lists or forums I follow evokes groans from the entire audience. Motor oil is a weird and semi-religious thing for some people and a thing you buy and put in your motor for others. One of my closest friends swears that Royal Purple is the best oil ever.
I have found that synthetic will seep between the seals on my 1976 motorcycle and dino will not. I suspect that if I rebuilt the engine and replace those seals the seepage would stop and all will be well.
More expensive is generally better in this study, but the "Platinum" seems to be an exception.
Image: screen grab