Not to be argumentative, BUT:

The first 1500 mile oil change is critical to getting the metal shavings out of the oil, which are bad for the system but are not going to choke the engine down. It's not going to likely matter much, but who wants those little metal shavings in there increasing friction and reducing mileage? No one does.

And on the MPG effect of synthetics, that entirely depends on the engine and the oil used. I went from Dino 10w30 in a 1997 Suburban to Amsoil 0w30, and I got a MPG increase from 17 mpg to 19 mpg, which is not much, but is actually a 12% increase. The effect will not be noticable in some cars, but what WILL INDEED HAPPEN NO DEBATE is that the engine friction will be reduced, which reduces the oil and engine temps and helps the engine in the long run. Synthetics reduce friction over dino oil because their molecules are uniform in size and the oil is "slipperier" if that's a word.

It's a personal decision to make, and there are millions of cars who have gone 150K with using Dino oil. But those same cars probably could have gone 175K or 200K had they used Synthetic oil all those miles. Synthetic oil is not a gimmick or a scam - it's actually BETTER OIL and anyone who cares about their car would be wise to use it.