I've used Mobil 1 in all three holes for the past 5 years. My 99 Ultra had 39,000 on the clock when sold, no problems at all, oil changed every 5000. I've had to switch to HD Syn3 because on one carries M1 here in Greensboro anymore for some reason. No clutch problems at all and the tranny shifts fine. I have heard folks say thay can tell a difference when they go to syn. in the tranny but I can't, I guess I'm old and my sences are dull.
IMHO this is one of those personnel choice deals and there will NEVER be an agreement on which is best.
Ride Safe