Phil: I own this lens and have to say I'm generally pleased with it. It works fine for still photos, and makes for an excellent video lens. What is most beneficial is that it covers the wide end of the zoom spectrum, through mid-telephoto. This is similar in length to the 24-105 for the 5D. If you're someone who likes to keep one lens on the camera, this is a terrific lens for that. The IS and USM are both quite good on this lens as well. This review is not without criticism though. And while subtle, I feel the need to point a few things: For being a 3.5-5.6 lens, the aperture closes towards the wide end rather quickly, reaching f5.6 at 60mm. This lens is also prone to vignetting if using a filter that isn't slim. This is mostly true on the 15mm length, at a small aperture (f16 and up). Not a deal breaker, but something to be aware of. Also, like many lenses not in Canon's L class, this lens is arguably soft at it's most open and smallest apertures. If you have a critical eye, and are even a semi-pro photographer, you need to keep this in mind. Everyone else may not even notice. The lens however is plenty sharp between about f8 and f22. The lens also isn't light. If you're someone who humps a lot of gear around, this may not be the lens for you. All in all, for what it does, considering this isn't part of Canon's "L" lens group, it is of very high quality and very versatile. This is my go-to lens that stays on my camera most of the time, despite my criticisms above, which can be worked around.

Arnt: great lens - sharp, fast AF, nice handling, nice focal length range for a walkaround lens. According to reviews and my own experience, it is on par with the famous EF-S 17-55. This lens is wider and longer, the 17-55 has constant f/2.8. It really depends on what you shoot most to decide between the two, both won't disappoint you in the IQ department

Dixon: This is a really great lens! It's very sharp and plenty wide for normal daytime shooting and it's OK at low light shooting (could have been my T2i that was bad). I took it on a two week trip to France and took wonderful pictures the whole time. My only gripe is that it is a very large lens and it is heavy. After holding it around my neck for a few hours it got to be pretty annoying and sore. This thing by itself is heavier than my T2i with the kit lens attached. So be warned! The focal range is perfect for a vacation, but it could be a little hefty depending on your situation. I highly recommend it!

Danielle: This was the first lens I rented from these guys. and the first lens I've shot with on my camera besides my kit lens. It arrived in pristine condition, and I had a great time shooting with it. Right now I just have the 18-55mm kit lens and it was nice to have a bit more zoom capability. I used it for a family shoot of about 30-35 people - big groups shots, and then I did the smaller family units. The focus stayed sharp & spot on, and I didn't notice a whole lot of distortion at 15mm. Then again, I didn't get too close when I was shooting at 15mm, either, to avoid just that. It did seem a tad heavy, but honestly I think that was just compared to my lightweight kit lens. I did use a tripod to get the bigger group shots but that was mostly so I could walk back and forth and check heads and faces without having to worry about recomposing. All in all a great lens. I'm saving up for one.

Peter: Purchased this lens used from BL. Fantastic lens. So sharp I had to adjust some of the picture styles settings I had dialed into my 40D to compensate for sharpness and contrast for my previous lens. Images have a "pop" to them. My post processing time and throwaways have dropped dramatically. BL offered fantastic customer service. I was a little worried buying a used lens sight-unseen but it is in great shape, performs flawlessly and I saved $150 for a great bit of glass. If you plan to stick with a crop sensor for a few years or longer this is the walk around zoom lens to get!

Rich: A great lens. Very sharp, good contrast, great colors, and fast to focus. The image stabilizer is much improved from older lenses -- it's possible to get sharp pictures with shutter speeds in the 1/8 to 1/5 range. I even got a handheld shot at 1/2 second (albeit at 15mm) that wasn't too bad. It's not a fast lens (you're at f/4.5 by 35mm, 5.0 at 50 mm), but that's what your prime lenses or for. It's also wider than most zooms. That extra 3mm on the wide end is very useful if you're in a tight room, or want to explore some wide-angle creative options. I rented this lens to shoot the cherry blossoms in Washington, DC and was very pleased with the results. So much so that I bought it a month or so later. Many of the pictures had a lot of "pop" to them, with great detail. It's now my default lens, and it does a great job in many situations.