Well, I'll bite. My 1998, Dakota had synthetic in it at 2,000mi. It did not break in until almost 70,000 miles. Break in defined as an increase in fuel economy AND power. We had a Van with a carbureted 318 (same engine as the Dakota) that my father ran on Dino oil until he saw the increase then switched to synthetic. It broke in at 13,000 miles.
I had believed the 'synthetic from the start' crowd and changed my first change at 2K. Looking back, that was a mistake. It cost me more in fuel and oil changes. Also, big mistake going to platinum plugs, gave my poor ol' 318 fits I thought were other issues. Cost me more for the plugs, wires, dist caps, rotors, coil, valve work, etc. Switched back to good ol' Copper plugs and all the issues vanished.
So, I've found the more traditional approach to be more effective for me, at least on the larger engines. I'll stick with regular oil until break in and then switch to synthetic on big motors.
Now, if you pay attention to the factory specs, even on those expensive BMW's, the engines are factory broke in so you don't need to start with dino oil at all, according to the factory. So take it for what you like. I took it at face value and my 2007 Caliber has had synthetic in it from the first change. Then again, at 1.8L it's so weak I wouldn't notice a break in change! Does get great gas mileage though.