Good condition - everything works beautifully smoothly as they should. Nikon mount is the best - has aperture ring, focuses in Canon (e.g. "correct"!) direction, and can use simple adapter to mount on Canon. Comes with case, hood and caps.
There are 2 scratches to the front element, but doesn't have any effect on images. As Sigma service engineer once told me "you can stick a postage stamp on the front of a big lens like this and you wouldn't notice"! Even so, this is reflected in the price, looking for 1,900 plus shipping.