Summary: The key reason that I bought this lens instead of the higher quality one of similar range with metal casing is because I'm a traveler. When I'm traveling, my Canon Rebel XTi and between one and three lenses go EVERYWHERE with me. Despite having rather high quality zoom and wide-angle lenses, the one that never gets left home is a nice middle-of-the-road zoom.
Summary: I had to replace my original Canon lens on my EOS T3i which was only a year old. That was a bummer, as the previous lens, (same one) decided to stop auto-focusing just after the 1 year Canon warranty was up. I ordered this one as it is a direct replacement for the one Canon sent in the box with the camera originally. I am very wary that this will also break as they seem fragile in construction and in operation, so I am watching my use with it carefully.
Summary: This lens is fine; it is a basic "stock" lens. It works well for taking portraits and close up shots. However, this seller is lacking. The lens came to me with auto focus not working. This is not a huge deal as the camera does manual focus, but auto focus is a nice feature. The lens also came with no lens cap and in minimal packaging. Beware before you purchase anything from them.
Summary: Purchased this lens as a wider option to the 28-135, knowing it was inferior glass compared to the Ultra Sonic or L Series line. But for the money it is a great option for stills because the image stabilization and auto focus are solid. The wider end of the lens is ok for video but pulling focus on this lens is a pain so it gets 3 stars.
Summary: Its a cheap lens so you can't expect much. I shoot with a rebel t4i and replaced this lens with the sigma 17-70 f/2.8-4 because f/3.5-5.6 is just to slow. I always have to turn up my I so so I can speed up my shutter and that causes noise. Over all its a sharp lens but very slow and when I had it I always wanted it to have a little more zoom.
Summary: I agree totally with the other reviewers who say that it's fine for basic "snapshots" but that's about all. If you're simply looking to step up to a Digital SLR from a point and shoot, then buy the Canon Digital Rebel XT kit that comes with this lens. It's lightweight and fine for nice quality landscapes and snapshots. This however would NOT be my first choice.