how often do you change it?
more often means less towards synth
how often do you sit at stop lights, around town stop and go driving which heats oil more?
More means more towards synth
how often do you run higher in the rev band?
more means more toward synth
personally, if i was driving it, on th highway at steady speeds mostly, and changing every 3k miles, i'd go with regular old oil.
the high mileage stuff is mostly bunk.
it has "seal conditioners" to help keep ruber seals in top order, however, being that they are sitting in oil, they do not need conditioning, unless they are abused by lack of changing the oil, overheating the oil, or outright just sitting there and not getting oil.
seals are killed by either dirt and otehr particles scoring their surfaces, or by drying out and microcracking their surfaces.
throw aq filter and oil at it every 3k miles and your good to go.....
(btw, my last vehicle, a tahoe, had 150k+ miles on it, all on reg oil, and b4 that a ford van with nearly 200k miles all on reg oil)