I've always run automotive oil in my bikes, from nitro 70 in the old days, to Castrol 20-50 nowadays. The knuck has over 70k miles, as does the 65pan. Bores are still serviceable, and bottom ends are tight. I do run the H-D canister filter and the tiny power steering cooler as an oil cooler. I'm sure the specific additives for mcy use are useful, but I guess I've been lucky with good oil that's filtered and changed at 5k or every season.
I like multi vis as it does start easier in cold weather, and is readily available when on the road. I've run pressure gauges on some of my machines over the years, and don't see any difference in oil pressure at operating temps, so I guess that new fangled multi vis technology must work.
Of course, oil is one of those things that everyone has an opinion on, and all this only proves I'm no different!