9 out of 10 points and recommendedSharp, distortion freeFocus speed isn't fantastic, hunts in low light
Very hard to say anything negative about the optical quality of the lens. It's excellent, sharp even at f2.8, bokeh is good too. No field curvature, no distortion to speak of. A bit of vignetting at f2.8, but nothing major.reviewed April 9th, 2012 (purchased for $320)
It does tend to hunt a bit for focus on my D5100 in low light, but in normal light it's fine.
As a macro lens it's a bit limited by the working distance, you need to get really close for full magnification, but when viewed as a general prime lens with the added bonus of being able to get really close it's great.
Construction quality is about as expected, it's a plastic lens with a metal mount. It feels no worse than the Nikkor 35 f1.8, and quite a bit better than the kit 18-55.
I've had the Nikkor 35 f1.8 before and I much prefer this lens, giving up 1 1/3 stop (where the 35 f1.8 isn't super sharp anyway) for close focusing is a good tradeoff for my use.