Mina arrived a few days ago and I took it out. A few things...attached to the 5n it doesn't feel any faster than attached to the C3 (I hoped it might be). The AF is unexceptional or perhaps "interesting" is a better way to put it. If you have a casual sort of approach to shooting with AF then you're good. If you want to to nail focus quickly and accurately then you might be disappointed. It close focuses nicely (I hadn't remembered it did that from my previous one) and has VERY nice IQ. It's sharp, nice bokeh and great color. If it were a MF lens I'd be talking it up all over the place. It locks focus pretty quickly in contrasty shots, not so much in low light. The touch to focus on the NEX5n makes it a lot more speedy to use but WTH...why doesn't it also fire the shutter? What an odd implementation of that kind of thing.
I like the lens and for $150 it's a great bargain. I think optically it's as good as my best MF lenses and if you're patient it's a rewarding lens to use. If the 16 is a s good I might pick on e of those up as well. They would make a nice little AF set for when you need AF and not break the bank.
A Boy and his...thing by dixeyk, on Flickr
This was shot in low light, hand held with the Sigma