A buddy of mine has a Ford - I think it's a Fusion, but wasn't interested in it enough to look - and it has the shut-off feature.
Riding around in it, I actually didn't notice it for some time.
It restarts instantly when he picks up the throttle, but apparently without the starter as in older cars.
Seems to me its main benefit is for passing the EPA/CAFE MPG & emissions driving loop test.