Are u kidding me? why i want to comment other brands? for what purpose? To prove the worst canon lens is better than the best lens of other brands?
If you think 17-85mm is cheap and good, just go ahead...hope you like it. Or probably you already getting one.
Well actually, in case my original post was overly harsh, what I meant was that the 17-85 is very capable of producing good images, no matter how much distortion it may indeed have. Frankly I used one for a week and didn't notice any except right at 17mm. It dissapeared completely at 20mm. Anyhow, with CS2's distortion filter, it can easily be corrected.
A very important thing for me that I liked about the lens was that it's sharp wide open. To me, I find it important that a lens is usable wide open, else it doesn't make sense to pay for the wider aperture. I'd rather you produce a 17-85/f8 if it's only sharp at F8 and charge me less.
However, given the price of the 17-85, I'd much rather go for one of the third party constant f2.8 alternatives such as the 17-50, 16-50, or 18-50 by Tamron, tokina and Sigma respectively if I was using a 1.6x as my primary body. To me brightness is of very great importance if I'm buying it for work usage. The 17-85 would be rather useful on a holiday, but I wouldn't use it outside of that circumstance.
My conclusion therefore, based on personal real world usage, as opposed to shooting test charts, is that the 17-85 is quite good, though it loses out slightly in terms of colour and contrast.
Canon will not think about releasing another lens for mid-range users because the 17-85 is widely considered to be quite a good mid-range lens, as the older FF 28-135 lens was. It is very unlikely that they will make the 17-55 cheaper as well because you cant afford it or refuse to pay for it. Canon's strategy is actually quite simple if you look at it, there's the 18-55, 17-85 and 17-55, all catering to different market segments.
Ultimately if you talk about useful range, everything is useful. There is nothing that's useless in terms of gear. Unfortunately, many people are trapped in getting better gear and eventually they become useless photographers because they spend so much time looking at test graphs, MTF charts and reviews that they never actually get round to using the equipment to produce images themselves.
What would be of far greater use to you in getting better images is reading articles on making images rather than gear. Gear only allows you to capture your thoughts, if those thoughts don't exist in the first place, the greatest gear in the world will be only capturing the rubbish that a brain outputs.