Very versatile, small enough considering range of optical magnification, inexpensive, excellent quality.

None I can see for my photography.

Best lens I ever used for very deep field people outdoors. Looks like 3D, with amazing details. Light enough for all situations, from up close, wide angle to telephoto. Outdoors pictures are the best.

Super fast autofocus in bright light and sports situations.

In low light situations a tripod is necessary and the autofocus feature is very slow

I use this lense on a Canon Digital Rebel XT/350D. The lense is lightweight enough to easily carry around without a problem. The autofocus works great in brightlight situations, but under low light is a bit slow. I used it recently for sports shots and they turned out wonderful. I did also use it at a wedding and do to the low light a tripod was needed to prevent camera shake when taking the pictures. For the price, this lense was a great buy.