The only cameras I was able to handle had the 24-70 (two examples, one stiffer than the other). It was a launch event, with probably 30 people passing three or four cameras around. There were probably single examples of the two primes, but I didn't get to handle them - I saw the zoom and a couple of adapted lenses (I wasn't really focused on the primes, because the zoom will be my choice for extended hikes).
Nikon gave an interesting 90-minute presentation, ranging from the durability and sealing of the body to the optical engineering behind the mount, then they did a hands-on. The presentation was very engineering-focused, interesting to the group of diehards who gave up a couple of hours in the middle of the day to be there, but I see what people mean about Nikon marketing - incredibly sincere engineers talking about the optical advantages of wide, shallow mounts are not going to pull in the social media generation.
If the Nikon engineers are right (and what they are saying makes sense), Sony has a huge disadvantage to contend with compared to both Nikon and Canon - their very narrow mount restricts lens design. The Nikon F-mount has the same problem, but film didn't need parallel light rays in the way that digital sensors do, so the F-mount made sense in 1959. At least according to Nikon, Sony made a real mistake trying to cram a FF sensor into an APS-C mount, especially when they didn't have a significant lens line (at the time) to preserve. Notably, Fuji didn't do that - an X-mount will fit a FF sensor as tightly as an E-mount will, but Fuji went with a new mount and a beyond-FF (I won't quite call 33x44 medium format) sensor for the GFX.
From MTF charts and initial sample images, the Nikkor 24-70 is a much better lens than the comparably-sized Sony "Zeiss" 24-70 f4, much closer in performance to the G-Master, which is close to twice the size and weight. Nikon is claiming (and showing MTF charts, for whatever they're worth) that the 24-70 actually (slightly) outperforms the newest version of their own 24-70 f2.8 used at f4. If so, that's a significant optical advantage for something they did - Nikon claims the mount is a big part of it, and I have no reason to dispute them. If so, Canon has a similar advantage...