I have used the new 15-85 USM IS lens for a couple days and am returning it with disappointment. I really wanted to like this lens as it appeared to fill the requirement for a very versatile "walk-around" lens based on a really nice range from ultra wide to moderate tele.

Here are my reasons for returning it:

--It is not particularly sharper than my kit (18-55) lens.

--It is not faster than my kit lens.

--The CA and edge performances are not exceptional.

--It is heavy, bulky, and expensive.

--At least on my sample, there is a little quirk in the image stabilizer which prevents it from working consistently when bursts of photos are being taken. It doesn't always settle / converge to its stabilized setting before allowing the shutter to fire.

For $800, this is entirely unacceptable, especially since many people (myself included) are attempting to upgrade from the 18-55 kit lens, and will make a direct comparison as I did. Given the huge price difference and really small performance difference, it is a hard lens to justify. I personally also dislike heavy and bulky, and this lens is both. The kit lens is light and small. And yes, I realize that "build quality" may recommend the heavy and bulky lens for those who toss their equipment around or drop it on the ground. I have never done either in 50 years of SLR photography.

Canon really disappointed me on this one, but I would reconsider this lens when it drops to half of its current price. Even then it would still sell for 3 times the cost of the kit lens and perform only marginally better. I know this price drop is unlikely to happen, but perhaps Sigma, Tokina, Tamron, etc. have a better value on the drawing board.....

Larry