Summary: I bought this lens because my original Canon lens was broken. For my amateur needs, it is very satisfying. The 1:2.8 aperture is great, and the building seems to be strong. The built-in zoom system is very interesting. The only con is that this lens is heavier than the original Canon.
Summary: I bought this lens instead of Pentax lens. I use this lens for boyscout activity. The lens is responding quick with auto focus. The picture is good. Specially in the shade I can open the aperture without the flash. I am happy with this lens.
Summary: I received a Canon EOS 7D in June and received this lens a month later. The lens is a good, solid performer, especially if you stick to f8. I have found that shooting in AV mode at f8 this lens is capable of taking very sharp pictures. This is no surprise - nearly every lens is sharp at f8.