after only half a day and 50 test-shots on a D70, it is quite clear to me that this lens is truly impressive. Image quality is slightly soft at f/2.8, but everything above f/4 is razor sharp and doesn't even need any post-sharpening. Contrast and colour are equally impressive.
The AF is the only point of criticism on this lens. It's not very fast and tends to hunt from time to time. Second, to select manual focus, you have to set it on both camera and lens. Bit weird if you ask me.
Furthermore, the lens is very well built and I was quite surprised it's not extremely heavy or big. Some might disagree, but I absolute like the hood which can be slit forward when needed.
And last: the focal lenght of this lens made me doubt a bit about buying this lens. 180mm incl. the D70's cropfactor is perhaps slightly too long for portraits and slightly too short for natureshots. Fortunately, there's more than that.