I've come to the conclusion that it doesn't really matter as long as it is motorcycle specific and even then, it doesn't matter much. Yes friction modifiers etc etc etc. And no, I'd never run it in my bike but guys do. For the record I think it is rather stupid to do that. But they seem to do ok.
But aside from going totally off the reservation and using car oil or something that does not meet the spec (which has changed over the years) although the engine hasn't much. Curious?
Whatever, amsoil, shamsoil, Yamalube, boobalube, Rotella, schmotella, pick your poison and stick to it religiously, or don't.
My favorite brand is called (clean and on schedule) and it has served me well even though the bottles change color from time to time.
There are way less refineries than their are oil brands. What does that tell you?
Remember, clean and on schedule. Get back to me after 250,000 miles or so to tell me how misinformed I am or that I was right.
I'll be out riding with some 4t whatever.