I had a chance to compare these 2 lenses and I was surprised that under these conditions, there was very little difference in the sharpness between the 2. Both shot at 200mm, f2.8, 1/400 and ISO 1250. These are straight out of the camera, no adjustments besides resizing. There is some difference in the colors, but that could easily be corrected post. Anyway, for those comparing the 2 like I was, if you don't need the added features of the IS II, you can safe yourself $1,000+ by picking up the non-IS.
Anyway, can you tell which one is the IS-II?