nowadays, anything can be called synthetic thanks to the castrol lawsuit.
you have to be careful and read the literature.. some amsoil products are just like mobil one now, in that they are group II or III mineral oil with solvents.. royal purple is PAO /ester ( esters counter the seal shrinking characteristics of the PAO ) blended with solvents just like everybody else, and redline is ester.
As for mobil one, rusty bucket is correct, they're taking the cheap way out now too.. the amounts of PAO are going down, while the amount of cheap petroleum fillers are going up..
something else.. when the oil companies say that " they're formulated to meet the tough 2007 standards" , all that means is that the zddp & phosphorus have been removed per the EPA.. those are your anti wear & anti scuff ingredients.. or should I say "were" your anti wear and anti scuff ingredients.
To answer the point of the thread, I'd recommend going 3k with the cheap oil, so the rings seat and any bearing material gets flushed out of there.. then PM me if you're serious about that engine lasting forever..