9 out of 10 points and recommendedimage quality, constant max aperture 2.8noisy autofocus, some vignetting on the wide end fully open
I bought this lens as a replacement for the Canon kit lens. I am perfectly satisfied with it and can recommend it to everybody. You would hardly find better lens in this price range.reviewed August 23rd, 2010 (purchased for $460)
The lens is sharp and has great image quality, the only downside is that there is some vignetting visible on the wide end when wide open (but that is not a big deal, see for example http://www.flickr.com/photos/martinpilat/4905305533).
The 17-50 range together with the maximum aperture of 2.8 make this lens almost ideal for indoor shots without flash.
I have some pictures taken with this lens in this set on Flickr
(taken with Canon EOS 1000D (Rebel XS)).
9 out of 10 points and recommendedprice, sharpness, build quality, sizenone
This is my first "L" lens and I really like it. The images are sharp, the auto focusing is fast. The build quality is superb.reviewed July 31st, 2012 (purchased for $700)
I love the look of the pictures the lens makes, the contrast and the nice bokeh.
I chose this one over the f/2.8 mostly because of the size. It is not very heavy. Also the smaller size is an advantage, if you travel a lot like me.
If you wish, have a look at some pictures taken with this lens in this set on my flickr. all were take with my Canon EOS 7D.