Honestly, the synthetic-blend aspect of MC is nothing but a marketing ploy. Its most likely a group II/III blend, with just enough grp III to move it into the same performance area as a pure Grp II+ base oil. This type of blend isn't uncommon.
Pennzoil has even said that their conventional yellow bottle is 100% Grp II+....but in instances where grp II+ isn't available, they'll blend some grp II with grp III to achieve the same performance level.
MC blend is a good oil, no doubt. But I wouldn't say its head and shoulders above any other conventional oil...and I don't think its meant to be, as its priced just the same as all the others.
MC Syn Blend may be the best conventional oil out there - no advertising dollars used to promote it , extensive R&D by Ford engineers and made to Ford requirements by Conocco Phillips allows for a modest price tag .
On my nearly new 10' Focus, first two oil changes were w/MC Syn Blend. Before leaving for a long trip I changed out the oil/filter but this time used Mobil Clean 5000. In my experience, the engine runs smoother w/this oil and the water temp guage is showing a slightly lower reading. The Motorcraft oil is very good, but I'm going to be using Mobil Clean till my stash runs out. I may run some of the Mobil Super 5000 on my next oil change just to compare.
I've run only MC 5W-20 in my 2002 F150 since new. First from the dealer changes then from buying it at WalMart. I've also used only FL820S oil filters since the first oil change. I run 1 year or 5,000 miles for my OCI, most likely it's 1 year. It works itself in the winter/spring and coasts in the summer/fall when I use my car. For ME it's the best bang for the buck oil change combo. I'll continue to do so until the truck dies in the far future
I also agree that it's in the same league, but not necessarily superior to, good dino's like PYB, VWB, Havoline DS, GTX, etc. If you have a dino 5w20 application, go ahead and use it.
MC 5w-30 and FL 820s filter is what my tbird got most of its life.
155k miles now and still going strong, and quieter and smoother than most newer cars our friends/family have.