Please see first the Mosaic Comparison Conclusions.
The bottom line is that if you stop down to the f/5.6 - f/8 range, all of the lenses can deliver very good to excellent results in most cases. So differences might come down to ergonomics, distortion, range, and quality at maximum aperture for handheld shooting.
My preference is for real-world field shooting, but this review focused on the mosaic comparison in order to provide a methodical survey of what can be expected. With nine lenses at 16/17/21/24/28/35mm, extensive field shooting as with my Zeiss Guide would have meant a month or two to cover all these lenses (at least), and I instead wanted to establish a baseline reference work for all the lenses involved.
Article continues for subscribers...
diglloyd Advanced Photography includes hundreds of pages of exclusive coverage and high resolution, Retina-grade example pictures detailing Canon and Nikon DSLR bodies and their lenses, with in-depth analysis of sharpness and contrast, color, bokeh, vignetting, distortion, MTF, and flare. Also included is a wealth of in-context technique and workflow insight. Since 2006, diglloyd Advanced Photography is the authoritative review and on-line reference for discerning Canon and Nikon shooters. Subscriptions cost $ per year.