I just bought a 10-22 Canon EF-S lens, as well as the 17-40/4L and 70-200/4L. I am not a professional, but it seems the 10-22 compares very well with the 17-40 in terms of build and initial image quality impressions. I've not tested it over a long period of time, but it's a solid keeper so far. Also, it takes the same lens hood as the 17-40, so if you have both do not buy the additional hood for the 10-22. It also takes normal thickness 77mm filters without vignetting--very nice for such an incredible coverage. Wide angle distortion can be very fun to play with, too. Good luck!