Excerpt: I bought this as an upgrade to my 18-55 kit lens that came with my T1i. I planned on using as my everyday lens. The first thing I noticed about this is that it is much heavier than my Canon kit lens...probably a good thing (better quality), but taking a bit to get used to. In the short time I have had it, I have noticed an improvement in sharpness over the other lens, but haven't done any straight comparison shots.
Pros: Easily Interchangeable, Fast / accurate auto-focus
Excerpt: I needed a lens for doing indoor photography at a work conference. The 2.8 worked nicely and I also used my external flash I was very pleased with the photos it took and the cost of the lens made it even better!
Pros: Durable, Easily Interchangeable, Fast / accurate auto-focus, Lightweight
Excerpt: Build and design features are very good. Has a lens creep lock. Image quality in well lighted environments is good. Low light environments are problematic, it produces significant noise. Since I shoot news, I prefer candid shots and don't want to distract the people I'm photographing with a flash. I returned it because of the noise issue.
Excerpt: I was lucky to pick up a used version of this lens for $280 for use with my Canon 5D Mark III (as a general walk around lens).I just couldn't see myself spending $[$] for the Canon EF 24-70mm f/2.8L II nor did I have the money for it.I agree with the other comments here on sharpness. A little soft at 28 + 75mm at f/2.8. But you only need to go as far as f/3.2 - 3.5 and the softness disappears.
Excerpt: I use this lens to photograph high school sports. It is fast enough and does a decent job. The pictures are not super sharp but for the price you aren't going to get super sharp. It is a relatively inexpensive glass and the pictures reflect that. If you want the super sharp photos you can spend 4 times as much for the L quality lens. For the price it is a decent lens.
Excerpt: I initially purchased a used copy of this lens, and was blown away with its performance. Very sharp in the center, acceptable sharp in the corners, and very nice bokeh. I did a wedding and was sold, my images were so much better than previous. The focal range on my DX body is excellent for me. Like others have said, 28mm is not very wide on a DX. I seldom hit this limit, but find I'm regularly zoomed to 75mm.