sensor based phase AF.. ready for the big boys? a few questions



i have not touched the nikon 1 system yet but i read that speed and AF are very good... right?

how is speed compared to phase AF in DSLR cameras?

how sensor phase AF holds up in low light situations?

what is your guess.. is sensor phase AF ready for DSLR cameras yet or not?

are there any infos how much of the sensor size must be dedicated to the AF pixels?
is it negligible or not?