This website has changed. It appears all the members on this board get so stuck in quicksand, making any conclusions about anything impossible, and have the mentality that $3 a quart Walmart brand dyno oil (API SN) is as good as any $10 a quart Synthetic, and that any engine can go 300k on either oil with no engine issues.
The fact is some engines are prone to sludge (Toyota engines from 1999, Chrysler Seabring engines, Honda 3.5 Liter VCM engines, etc). Oils that resist sludge can make a big difference is those engines.
Also, engines with 150k miles on them can have engine wear that means clearances get larger, and then mechanics say to use thicker oil to fill the large clearances to keep oil pressure high enough to circulate. So engine wear is important.
If Penzoil Ultra Platinum is the best oil on the planet, giving lowest sludge levels and lowest oil wear metals, and we can prove that scientifically, then this website and its discusssions really have value.