I picked up a second hand Sigma 70-200mm os for $750 Aussie dollars, from a guy who wanted to upgrade to the Nikon version. His lens came to me and it looked brand new. I was so pleased - I never would have been able to afford any of these lenses otherwise. I love the Sigma, and I can agree that it feels quite tough and the focus ring is tight and wont move by accident, but the finish might scuff easier than the Nikon or Cannon