Summary: Here's another case where it all depends on how you use it and what you expect. Personally, I like really sharp images. This means, I can photograph something that has a lot of detail and examine the corners of the image at 100 - 200% and "read" what's there. If this sounds like you, then this isn't what you're looking for (unfortunately, neither is the 24-70 L but its much closer).
Conclusion: Not a bad walking around lens in bright conditions or for general grab shots. Much better than kit 18-55, particularly stopped down. Want pin-sharp results throughout the zoom range and a usable f2.8? Time to shell out that extra $1,000 and get the 24-70L.
Pros: Light, inexpensive, good range, USM/FTM, produces decent images if not pushed to its limits.
Cons: Build quality a little weak, images soft wide open.
Conclusion: i wasn't very hot for this lens after reading some of the reviews but i really needed a light weight zoom for travelling. i tried this lens in a food studio session, and the results are not bad, though not as good compared to the other lens used, the 50mm 2.5 macro. i don't regret having purchased it.
Conclusion: I bought this product one year ago in B&Hphotovideo in NY and I was quite happy then... But, When I brushed my skills in wedings and fashion division I understood that this is not a good glass for me niether for serious customers!!! I dont want to make wrong opinion in readers head about this lens but I worked only with this peace of glass on Adriatic See this year and used Velvia 50 film...and what I found?
Pros: Light; inexpensive, fast AF, portrait lens at 85...
Cons: Vigneting at 24mm...even at 85 on the edges! 67 filter size, f/3,5-4,5 not so sharp for zoom standard at f/3,5- 8 etc...
Conclusion: This lens is a good standard zoom and surely a great improvement over any kit lenses. Wide open it is rather soft, but stopped down a bit it is really good. USM makes the AF fast and accurate. Since I often find myself pushing for the ISO800 and still ending up shooting wide open, I think it's time for 24-70/2.8...
Conclusion: It's ok quality, considering the price I paid. Not as sharp as other prime lenses i have (of course), but easy size to carry around. Appropriate for everyday snapshots, especially with DSLR, which you might wanna be more careful about lens exchange to avoid introducing dust on image sensor. I'll bring this one with 10D for travel situasions.
Pros: small size, low price, fair image quality
Cons: zoom creep, barrel and pincushion distortion