had to give this lens an average rating ..after less than 6 months my IS broke, needing new mother board ( and some other parts) then it took me 2 more attempts to get it back to decent focusing( they claimed it was set to factory specs but it was unusably soft and CA was terrible, on repair attempt #3 they said the focus was off electronically what ever that meant )...I liked it before it broke, hopefully the repair will last but kind of soured me on the lens. IS is a great feature if it works but a headache if it doesn't. The whole lens would not focus or take a photo at all with it not working right.

This lens is optically as good or better than any of Canon's other midrange zooms that I have used including the 28-105 f/3.5-4.5, the 24-85, and the ugly 35-80. What sets it apart is the IS. The usefulness of IS on a lens with this range can not be overestimated. I disagree that IS doesn't help this lens as much as longer ones - I regularly shoot this lens at 1/4 second and get sharp results. With the 300 f/4L IS I can't reliably go below 1/20th. Wide open the performance is OK, going to great at f/6.3 and tapering off rapidly after f/13. There is some distortion. Unlike some others my lens does not creep at all. This lens does not remain in consistent focus while zooming, and I also occasionally detect a slight focus shift when stopping down.

I've owned this lense for about 5 years. Very good overall lense in its price class. Light and thus suitable for overall and travel. I've actually used it for product photography and it was ok. Also a good choice for a first lense. The max aperture does not allow powerfull bokeh. Focus accuracy ok, speed also ok, yet not as fast as say EF70-200/2.8.

IS not as much help as with longer lenses.Build quality is typical for hi-mid range lense. Some dust creeps in with time.

Definitely a lot, a lot better than say EF28-90. Probably my most used lense over time.

Great lens,
the range is perfect for a mid-tele lens.
a bit of zoom creep.

Great lens, and a great range. The ISM makes this lens, and I will say that it is sharper than a lot of people think. The ISM improves the sharpness of my photos a LOT.