I use it in my little Scion TC. Its more expensive but the extra mileage between oil changes seems to average out.

I found this on wiki:

Advantages

Better low- and high-temperature viscosity performance at service temperature extremes
Better (higher) Viscosity Index
Better chemical and shear stability
Decreased evaporative loss
Resistance to oxidation, thermal breakdown, and oil sludge problems
Extended drain intervals, with the environmental benefit of less used oil waste generated
Improved fuel economy in certain engine configurations
Better lubrication during extreme cold weather starts
Possibly a longer engine life
Superior protection against "ash" and other deposit formation in engine hot spots (in particular in turbochargers and superchargers) for less oil burnoff and reduced chances of damaging oil passageway clogging.
Increased horsepower and torque due to less initial drag on engine
Improved fuel efficiency

What Ahpook said.

It has additives to recondition seals and such. It's not meant to last longer than other oils before needing to be changed. You can get high mileage oils in either synthetic or conventional formulas.