Well, as a commercial trucker who owns the trucks (class 8), and having over 5 million miles under my seat, the argument that Rotella saves money and mean time between overhaul is not quite a valid argument. All of the major brands do quite well. I took a Cummins N-14 to 1.4 million miles (only 1 injector and an accessory drive seal replaced) and it still ran great and went right to work for the next owner. All on a Kendall 15w40 conventional and getting 30,000 mile oil changes and just stock Baldwin filters. Mobil Delvac, Chevron Delo, Shell Rotella, Schaeffer, etc all have quality oils that will do the trick. There is no one perfect "best" brand. I have seen HD truck engines grenade on all the different brands. I have seen many HD trucks also go to some incredible miles on the different brands with no major engine repairs. I had a Cummins ISX 15L that got fed a Rotella and it ate cams. I think that was mostly metalurgy related, but it didn't bode well for the Rotella protects better argument.
Engines are like firearms. I can get two fine quality .22 rifles, feed them both a fine quality ammo, and get different results. Nothing wrong with the guns or the ammo. I can then try a different fine quality ammo and the results will be different again. Some engines will do best on a Delvac, some will do best on a Delo, some will do best with Rotella. One of life's little mysteries. My current Detroit 60 12.7L is at 608,000 miles on a Schaeffer brand oil and it only uses 2 qt in 22,500 miles (50% longer than OEM recommended drain interval on this engine). Doing great and oil samples very good.
The key is getting a good quality oil that your engine has a personal liking for and meets your operational needs, and getting the best value on purchases. There are quality oils in all the major brands.
Yeah this was back in the 80's and early 90's.