I had one mate ,on my d300 it was ok up to about 400 over that it was very soft...save for the 50-500 or the new os one...much much better...
sorry mate, read it wrong ,I thought it was the 170-500.....I thought the 150 - 500mm Sigma already had OS?
After hours of conflicting comments about the lens, I have decided to use my 3oof4 with a 1.7 or 2x TC and keep all my glass NIKON and be none the worse off. There is some confusion as to whether the 2x will allow autofocus
I also read that the 300F4 won't auto focus with the 2X TC but would with the 1.7X TC.