But yes, I agree. The results are terrific. I imagine that Mackguyver (easily this forum's most avid discussion person on this lens) probably had kittens reading this article.
- A
What lens? Oh that one, yeah, I suppose I've discussed it a little bit

and I love the having kittens phrase - I haven't heard that one in a long time!
The article was quite interesting and I was happy to see how it compared to the Nikon 14-24, but I think we'd all like to see how these lenses compare at f/11 & f/16 where they are most likely to be used for landscapes. Roger's doing this for free and only has so much time, of course, so anything he does is greatly appreciated.
His comparisons seemed to match what I've seen in comparing it to the TS-E 17 and other lenses. To me, the biggest difference between the new 16-35 f/4 IS and the f/2.8 is the color and contrast. It's extremely similar to the 24-70 f/2.8 II and the difference between the f/4 IS and f/2.8 II is very much like the difference between the old 24-70 and the new one. Photos have that prime quality to them (minus the aperture, of course) and I'm really loving the lens. The vignetting and distortion are a bit worse than the old lens, but the Adobe profile works great and DxO's profile is on the horizon.
The sharpness is equal to the TS-E 17 (at 17mm) and 24-70 f/2.8 II (@24mm), but is bested by the 24-70 f/2.8 II at 35mm and the TS-E 24mm at 24mm. I had already sold my 16-35 f/2.8 II, but in previous tests against the 24-70 f/2.8 II, it looked like a mushy mess at 24mm in comparison, at least for the outer 1/3 of the frame. The test also showed me that the TS-E 24mm is one damned sharp lens, no matter what Roger says about it vs. the 24-70 f/2.8 II.
The only truly bad part of the lens was comparing it to my recent TS-E 17 f/4 and finding that while it's just as sharp, the 17 has noticeably less contrast, more muted colors, and more CA. The consolation is that the 17 has almost zero distortion and vignetting (when neutral) and did I mention it tilts & shifts?