I purchased this around 6 months ago and have taken ~2k shots with it by now.
Very good lens overall, my only issue is the sharpness at wide open, it's sharp but not as sharp as I would like. The auto focus is always spot on and silent. The fit and finish are excellent (as are all Sigma EX series).
As in life you get what you pay for, this is a US $900 lens, if you want sharpness all the way across get the US $1700 Nikon lens
This was a good purchase in my opinion