I have had this lens for a few years now. I use it on my Canon EOS film camera. I think for a hobbyist it is a wonderful travel companion, but it is not a serious lens for pro use. The auto zoom function stopped working, but Sigma fixed it for me within a week. That happened in year 2 or 3, so the unit was out of warranty, the cost was about $55.
A note to Ohansen, there is a lens lock that prevents the lens from extending while not in use. The lock looks like the Auto/Manual focus switch and it is close to the mount.