Summary: First off, the title of the product page says "for Nikon". I bought this lens for half price on e-bay but new, in the box. I paired it with Nikon 3100. The lens works fine in a room with flash but outside it was a nightmare.
Summary: I purchased this zoom to use with a Sigma SD1 digital SLR and the combination is really excellent. Its smooth operating, of good quality, and produces very sharp photos at all aperatures and focal lengths. This is a very good "kit" lens.
Summary: OK, perhaps it isn't perfect, but it is darn good, and amazing for the price. I'm a small guy who lugs around a 60D on long trips. Things get very heavy very quickly. If I had my druthers, I would carry this, my 50 mm Canon f1.4, and my Canon wide angle.