Someone can correct me if I'm wrong...but I can swear I remember reading that Mobil 1 used to advertise 25,000 miles between
oil changes with the
synthetic.
But of course, imagine if you were burning a quart of
oil every 10,000 miles. At your 25,000 miles
oil change your 2.5 quarts low.
I run Mobil 1 in most of my cars, used to run
Amsoil. Mostly comes down to the fact that I can get 5 quarts of Mobil 1 at Wal-Mart for $18.88.
Amsoil is much more than that, and not as easy to buy on the fly.
-steve in nj-
Oh, and as for the 0W-30, I noticed less startup noise when using it over the cold winter months in cars designed for 5W-30.