Hi, I am using 14-150 on E-P1 and it is very fast to AF in bright light even on the otherwise slow E-P1.
On E-P3 it has to be even faster, but I suspect that the newest "R" lenses will be a bit faster.
There is a firmware update for 14-150, BTW, which is supposed to improve AF speed on E-P3-series of PEN cameras, but I have not tried it yet. No idea if it will improve AF speed on E-P1 either.