You will only Have Autofocus, if the adapter AND the lens you use have Autofocus Capability.
I personally own a NEX 3, and a Canon 50D. I have Adapters for both to use LEGACY lenses, or lenses that were not made to be used on these cameras. I prefer Manual focus for my Street Photography and Candids, But when its business time, Its Autofocus or the moment is gone.
The difference that the NEX and the Nikon have, is that Nikon has been making lenses for the current line for over 10 years, the same electronics in the mount, and that leaves a lot of space for 3rd party brands as well.
NIKON only advertises their own lenses, and there are at least 10 other Manufacturers that make lenses for Nikon as well... so that 160 figure is just the tip of the iceberg.
Also, you really need to figure into the equation, the use you plan on getting from these cameras... Porsche makes some Great Sports cars, but if the speed limit in your state is 35, you could simply buy a Volkswagen.
This is not comparing the cameras, but the Lenses they have available... You can Easily spend $2,000 on a single lens for the Nikon, and really only need a $150 lens... meaning.... out of the 160 available, there are probably only 5 that might have any use for you... so basing your decision on that figure is useless.
