Mobil 1 in new cars, and "break in"
I noted your comment about new MBs coming from the factory with Mobil 1; and I've heard that before.
I've used synthetics for over 25 years, but always after a generous break-in period, as recommended by the oil manufacturer. So it's interesting that, here, synthetic oil should be used right away -- unless there is some "break-in" version of synthetic oil that I've never before heard about.
I'm starting to have an old engine (M110) (on a used car I just bought) rebuilt (including hones cylinder walls and new pistons, cams, etc.), and now I'm wondering if I should start the new engine on synthetic oil right away, or wait per my usual practice.