You should directly compare the 14-24 corners to canon's 16-35 corners. Sadly (and I own this lens), Canon's corner and edge performance is really atrocious.
Yes, I decided to forego the 16-35 in for the 17-40 instead; was definitely better for landscape type shots from what I saw.
Interesting, that while Nikon and Canon have chosen different paths, the final results are quite similar...
yes, in most cases.
Seems like WA zooms for FF are a weak area, likely difficult to design; I've yet to find a satisfactory WA zoom in the 16-18 to 35-50 mm range.
It looks like the lower end Nikon 18-35mm is winning for performance/cost right now. Add a 14mm Samyang for that extra wide shot and I can save a bunch of $ as well.
I've got a Tokina 17-35/4 which is very nice from 21-35mm but the 17-20 range on mine is very soft on one side so will be sent in for a warranty tweak. I also had the Nikon 17-35/2.8.. sharp in center but performance fell off quickly so even on a crop body it had poor corners.
I just got an old Sigma 17-35mm which I've yet to try.
Hopefully Sigma or Tamron will throw their best lens design software at this problem and come up with a better solution soon if the OEM guys don't provide better.
BTW, if you're into astro, I've heard Samyang's 24mm is also good as far as coma is concerned.