NEX 5n autofocus speed - need a bit of advice
The 5N is pretty quick IMO, but I never compared directly with the Nikon. My impression from reading reviews is that the newest M 4/3 bodies and the Nikon are on par with the fastest AF, and the Sony NEX are a step behind (but still pretty capable.)
I have 2 daughters and don't find the NEX-5N AF a problem with the kit zoom or 16mm pancake for candids.
I believe the 5N is supposed to be a bit faster than the other NEX cams due to more processing horsepower.