HERE on an oil forum, WE have people trying to go cheap and use a 10w40 in a Harley. I don't get it. I suppose you guys know more than the Engineers at HD. I'm OK with using any 20w50 oil not necessarily an HD brand. By the way Big Twin HD's have a VOLUME oil pump. Not a Hi-pressure pump. When you hear your lifters making noise, your oil pressure is probably too low. This can also happen when you use too heavy of an oil in low temps. (like a straight 50 weight in 32 degree weather) Lets hear about personal experiences using the correct oil weight that might affect engine longevity. For example, a lot of people really like Mobile 1 MC oil. I had a bad experience with it.
I've rebuilt a lot of Harley engines over the years and had the chance to observe a lot of riders using a lot of different oils over time. Barring egregious foolishness (like the guy who ran the cheapest 10w-30 he could find or the guy who ran gear oil because it was heavier and therefore better) with one exception it is less about the oil and more about the person's riding habits and maintenance habits.
The exception first -- certain oils do not work with the cam profiles on Harleys. Think about the difference in the wear surface between a relatively low lift overhead cam and a relatively high lift cam with roller tappets. The wrong oil results in skating on the cam lobe ramps and as the valve springs weaken you start seeing bounce at the top of the lobe and the hard facing starts shattering. This causes a lot of wear and damage, far more serious than choosing 10w-40 rather than 20w-50.
It's worth noticing that there are plenty of Evo engines that went well over 200,000 miles on HDEO multigrade, I rode one that had been on Rotella since it was new, it had a little over 249,000 miles on it and other than repairing one leak it had never been touched with a wrench except to change oil and spark plugs and it ran like new.
The main sources of damage I've seen over the years in order of significance:
1) Revving the engine at cold startup. Let it warm up just a little bit first.
2) Rough treatment. If you are going to do hole shots or burnouts or wheelies at least load the drive train up a little first and have some finesse with the clutch. Taking the slack out before you apply power reduces damage greatly.
3) Oil change interval in hot weather. Harley published some guidance from the factory school when they first started recommending multi-grade oil that said every 20 degree increase in oil temperature over a certain point cut the oil life in half. I don't know if that still pertains, if the chemistry has changed, or the research indicates something different, but I can say with certainty that people who shorten the OCI in hot weather tend to get more miles out of their engines before a rebuild is required.
4) Too much oil and/or too much oil pressure. Whether it is oil that is too heavy for the climate or any of the aftermarket gimmicks that pander to "more is better" mentality, too much oil and/or too much pressure is rough on these engines. Roller bearing bottom ends just need to be wet, that is about all. I've seen bikes run for years with the oil light coming on at a low idle. There is a reason why Harley sets the relief valve pressure the way they do. And yes, if hydraulic lifters are clattering at an idle it's worth making sure they are getting the design flow (like clean the tappet oil screen on an older engine) and consider using a heavier oil under those conditions.
If you follow the manufacturer guidelines for oil type and viscosity and change it at the required interval or sooner under demanding conditions you're going to be fine. Any of today's premium name-brand oils formulated for V-Twin motors are going to work. I am careful about using automotive (passenger car) oils, the savings on the cost of the oils doesn't even come close to the cost of the damage I have seen if you choose wrong. As for HDEO, there is no reason to not use it in moderate climates if you are inclined that way, it works great up to about 80 degrees ambient.
To the OP question, I run Valvoline VR-1 (their racing oil) in the engines I have bumped up a bit, the oil is quite reasonably priced, it seems to hold up well in engines that are running hotter or under higher compression, and I just change it a little more often. Upon disassembly what I am finding is an engine that is worn as expected (tolerances all a little wide) but no scoring, even wear on pistons and cylinders, no unexpected discoloration anywhere, no mechanical damage to bearing surfaces, no shattering on cam lobes, the engine looks great, just worn out.
Everybody has their preference, anecdotal evidence abounds, and I am certainly not going to advocate one brand of synthetic 20w-50 over another. Just offering my own experience, maybe it will be helpful.