On 3/27/2021 12:06 PM, mike wrote:

What I need now that I'm shifting from conventional to synthetic is a good
way to tell the quality of any two oils from just the packages in my hands.

As you can tell by now I don't get my facts out of my ass so I'm willingly
admitting openly that I don't yet know how to compare any two synthetics.

Do you?
Does anyone?

How?

If a synthetic meets the requirements of your car it will be suitable.
Synthetics are superior to conventional.

As to Brand X vs Brand Y, I've seen some "tests" but nothing meaningful.
One YouTube video was a given amount of oil spilled on a track and the
time to run down measured. Huh? Has nothing to do with performance in
your engine at 6000 rpm.

A real test would be a series of sleeve bearings run for many hours,
each with a different brand of the same viscosity oil and the shaft and
bearing measured for wear. Another could be the power required to turn
a shaft at a given speed using different oils.

I'm sure there may be minor differences but I don't think any would be a
bad choice.