Actual Mobile One Experience
I have a 00 Maxima SE that I bought new in Sept 1999. I changed the regular oil at 2,000-5,000 and at 10,000, switched to Mobile One 5-30. I have the dealer do the oil changes and I provide my own 5 gallon jugs of Mobile One 5-30. I have used the standard OEM Nissan filter and change both oil and filter at every 5,000 miles.
The car now has 135,000 miles on it and the engine has no measurable wear on it. I had a compression test run at a non Nissan dealer at 100,000 miles and all the cylinders measuered with in +/- 2 of each other. The technician who ran the test, ran it again because he couldn't believe they were still that close after 100k.
The car gets lots of highway miles (driving 75-85, usually) and has achieved a lifetime Gasoline mileage of 24.2 MPG on Amoco Premium, virtually every fill up. The mileage during the first 10,000 miles was 22.0 (with the same kind of driving, except for the first 1,000 miles where we followed the break in schedule, well mostly).
I know I'm spending a little more on oil changes (I've explained it to the wife many times!) but I'm saving close to enough in gas mileage to feed it the good stuff all the time.
I suspect I'll get a similar gas mileage result when I convert the Murano at 10,000 miles but the extra wind resistance may reduce the gas mileage increase a bit.
This was the first vehicle I ever ran synthetic in but now I'm a convert and I use the small remainder from the 5 gallon jugs in the lawnmover and string trimmer as well.