I got a great deal on a used one. The lens is just magnicifent. I have always been wary of the quality of zoom lenses until I bought this one. The L series lenses are definitly a class above. My copy is very sharp.
The range is perfect for landscape photography though I've been using it for ebay - larger item product photography as well.
17mm on a 35mm or full frame is absolutly awesome. Of course it has distortion, but not nearly as bad as I would have thought.
Excellent lens, I will keep as a permanent resident in my bag!