No intentions of starting a heated debate, but I wanted to post a little data.
I was reading an oil analysis data post made a few weeks ago.
The poster was using Amsoil 15W40 and had some pretty good reports from analysis.
I thought that I would share mine.
I used Shell Rotella 15W40 for the first 28k miles then went to a blend of 8 qts reg. Rotella and 2 qts syn with a Wix filter. Oil changes are done every 6k miles

My Avgs. My Most Recent Amsoil Post from 8/17
Alum. 3 3 10
Chromium 2 1 8
Iron 25 16
Copper 5 2
Lead 4 4 12
Tin 1 0 <1
Molybdenum 1 1 <5
Nickel 0 0 <1
Manganese 1 0
Silver 0 0 0.1
Titanium 0 0 <1
Potasium 6 7 <10
Boron 3 1 10
Silicon 7 2 9
Sodium 3 3 4
Calcium 3186 3196 4667
Magnesium 10 8 305
Phosphorus 1102 1033 1412
Zinc 1263 1227 1436
Barium 1 0 36

I must say that the Amsoil unit was purchased used, so the owner had no control over the care of the unit prior to purchase and it has a few more miles than my unit.

Now I am not trying to bash Amsoil. I use Amsoil in my boat and have an Amsoil air filter in my truck.

I am not going to make any judgements on the data. Just thought that I would share mine