Processing I find fine, the lens makes a high impression. The zoom ring has exactly for me the right rotational resistance, at least in my lens extends far also not alone if you have the camera slung nearly horizontal. Only when the lens is almost vertically downwards, it may happen that it automatically moves out while walking. I have no problem with that. And besides, there is still a lock switch that prevents the extension.
For me, a great objective, especially with regard to the price-performance ratio and which is suitable for most situations. If you want more, you have to look at the four-digit Euro area or without the large focal length range and buy a Fixfocusobjektiv.
Tested with Nikon D70s and Nikon D90.