Well, as mentioned before, lots and lots of Used Oil Analyses (UOAs) show Pennzoil Platinum (PP) and Quaker State (QS) as being much better than Mobil 1 in protecting your engine from wear.
I won't rehash the details here, other than say that respected tribologist Terry Dyson of DysonAnalysis.com (with over 30 years of experience) has said the same.
And there have been independent studies showing Mobil 1 (M1) not doing as well as PP. I've lost some of these references (perhaps I should have posted them here when I first read about them), but one that I remember off-the-bat can be seen at Amsoil's web site at this page (look at the graph midway down the page):
The Amsoil product is not easy to find; it's not an off-the-shelf oil like Platinum and Mobil 1. But you'll see that the easily available Pennzoil Platinum, Halvoine, Quaker State, Motorcraft, and Castrol all performed much better than Mobil 1.
So why spend the extra money for an underperforming oil?
Notice that the wear in millimeters for Mobil 1 is greater than
1 mm ( >1 ) even though the graph ends at 1 mm.Regarding the synthetic versus conventional debate, please keep in mind that careful, scientific studies have shown that 90 percent of engine wear occurs at cold startup and within the first 15 or 20 minutes.
A non-affiliated PhD writes the following about a paper by Schneider, et all, called "Effect of Break-In and Operating Conditions on Piston Ring and Cylinder Bore Wear in SI (Spark-Ignition) Engines":
"The rate of wear is much higher within 15-20 minutes of start-up than after reaching normal operating temperature. There was a lot of data but I conclude that the initial start-up time period (first
20 minutes) result is 100 nanometers of wear whereas the steady state wear rate was only 4 nanometers per hour thereafter. (Hence we should be concerned about start-up oil thickness more than running thickness." [END QUOTE]This is another reason to use synthetic oils, since they're much less thick at very cold temperatures, and can start lubricating your engine better and faster during wintery cold temperatures.