I find the 17-40L to be a great walk around lens on a cropped camera particularly for landscape photography. I don't see any noticeable softness at any f-stop or focal length in prints up to 8x10. AF silent and quick.
Would the 17-40L be better if it had with a wider zoom range and was a bit faster (2.8) - sure! But, for what it does, its a great lens!