Mobil 1 - They changed their formula from 100% PAO/Ester to about 40-50% several years ago, so we must punish them severely (even though PP is a Group III oil). Besides, they are top dog, and everyone loves the underdog. Then add in the all the false rumors about Mobil 1 from the competitors (many of whom post here), and Mobil 1 is now the Darth Vader of motor oil.
Castrol - Syntec deceived everyone in the late 1990's by calling Group III a synthetic, and their advertising is still questionable and increasingly obnoxious. Edge looks good but is hideously expensive in 5-quart jugs. Besides, I wouldn't buy a British car (nothing to do with politics), so why buy a British oil?
Quaker State - The other half of the Shell USA duo (along with Pennzoil) seems to be marketed at oil dummies these days, and unless you believe in the fairy tale about "Pennsylvania Grade Crude Oil" (which are not even used in the synthetics), then why bother? Besides, green is not my favorite color.
Valvoline - Their first attempt at a synthetic was less than stellar, although it has apparently improved recently. Valvoline was thought to be an good-ol-boy "All-American oil" based in Kentucky, but now we know they get most of their base stocks from Motiva Enterprises LLC, a joint venture of Royal Dutch Shell and Saudi Refining Inc, so the bloom has faded a bit.
Amsoil, RP, etc. - Maybe good oils, but outrageously expensive, and no really seems to be sure anymore whether they are API and manufacturer certified.
Pennzoil Platinum - This leaves PP to to win by default. Besides, Johnny is regular poster here, and a really nice guy.