Surely it's on'y the extra focal length you miss?
The 17-55 2.8 is supposed to be very sharp?
Yes, I miss the focal length range of course, but the 17-55 2.8 is also a lot heavier. That's the penalty for f/2.8. You know you're carrying it, and for walkabout when maybe photography is not number one, that's a consideration.
Also, since I bought it, I've got to use Canon's DPP software and it is very clever and effective especially with a lens like the 17-85. All those optical shortcomings that we pay a fortune to get rid of in a lens, banished in the click of a mouse in software. If I was to say that DPP turns relatively humble lenses like the 17-85 into L class, people would think I'd gone mad, but if you take a look at the images, and see the standard of quality, well... try it for yourself. And in the next generation of cameras, this will all be done in-camera and you'll get superb quality JPEGs straight out of the box. It's the future I tell you
Getting back to the point, yes the 17-55 2.8 IS is very, very sharp indeed. And at the long end, there is a big difference between f/2.8 and f/5.6. It's a thoroughly sorted lens all round and I will not be parted from it, but I don't kid myself that there are much cheaper ways to get images that are pretty much as good most of the time.
