Wow. Never fails to amaze me at how emphatic people get when talking about motor oils!
I will give some backing to the notion that the current Mobil 1 is not the same Mobil that we've all been buying for the last decade. I will also agree that Royal Purple is a bunch of marketing fluff.
As for what's going in my car: Lubro Moly. Has Porsche's blessing, and is made in Germany to boot! "C'mon, you know the Germans make good stuff."
In a final closing point, in my opinion, unless you're buying the cheapest Walmart branded stuff you can get your hands on, any of the modern oils are fine in your car provided that you change it more often than every 20k miles.