Strong vignetting, clear chromatic aberration, poor kanskärpa and additionally becomes the horizon curved like a cheesy puppy if you take a panorama (cant term for this). Mine is not even a year old and you can already see the dust on the inside of the front glass.
On the positive can be said that the autofocus is fast and quiet. The image stabilizer does a good job, and 17-85 is a good range but it does not matter as when there is so large central flaws.
Edit: Bought a 17-55 2.8 and it actually has the same strengths and weaknesses as this lens. Because this must be about the best you can get, I think 17-85 is very affordable, especially as used. I will keep both because 17-55: an is a big lump is not wanted anywhere.