I bought this lens about 4 months ago as a Christmas present for my wife to use with her Rebel XTi. When I received it I was very happy with the quality and build of the lens. It has a beautiful matte black finish and feels extremely durable and sturdy. The OS worked great too, reducing blur by up to 3 stops in manual situations for me, maybe more for those who can hold on tighter than me. My wife LOVES the lens because her shooting modes are wide (landscapes) and then she can suddenly switch to medium to large zoom (abstract pictures of objects etc.) and then back again. Before this lens, she had to constantly switch back and forth between her 18-55 kit lens and her Canon 70-300 IS USM lens, or simply skip a shot because it was impractical to switch at the time. Sigma changed that. Now their kit lens is practically obsolete as this lens has a focal range of 18-55 and has optical stabilization which the kit lens doesn't have. Focal lengths, but we haven't seen any signs of them. In fact, at 18mm, images appeared sharper and brighter with this lens than with Canon's kit lens. As a serious hobbyist, she is very happy with this lens. However, after using the lens for a few weeks, she started showing "Err99" on her camera from time to time. We isolated her from the lens as she had 4 other lenses - 2 Canon and 2 Sigma (55-200mm and 10-20mm) and in the 15 months she has owned the camera she has not had this fault on any of them lenses. other lenses. I wrote to Sigma about this and they were very apologetic and helpful. They said it sounded like an "FPC cone problem" and recommended I send it in for repair as it's still under warranty. Copy but I haven't seen this issue in any of the other reviews I've read here for this lens. This error message was the only downside to a lens I don't regret buying. Apparently my wife liked this lens so much that instead of getting a refund from Revain and buying a different brand/type lens, she decided to send it to Sigma for repair so she could keep it. As others have pointed out, the zoom and focus rings are very close together, but we both got used to them after just a few uses. 3 out of 5 stars because of the error message.