EM-5, AF on moving toddlers?

Ok, I hear the EM-5 has the fastest AF in the game. I am curious how people's experiences are shooting pics of little kids that never stop running, turning, moving? Is the AF fast and accurate, or just fast? Do you get a good keeper rate? Is it fast, faster than a dslr? When they say it's fast,  is it fast for m4/3 or are people dropping their FF for sports? Shed some light on the moniker 'fastest AF'. I am temped, but want to get a better sense of fast.