The more I read about the Z7, the more I'm convinced that my decision to get on the list was right - it's the best match for what I'm doing - landscape, often involving very long hikes (not necessarily the best choice for everyone - I can see merit in all the systems, depending on what you're doing). I don't have one yet - I'd be posting photos if I did - hopefully soon, I can't wait to use that big ol' sensor for fall color!...
Here's Why:
1.) Big pixel count (while keeping pixel size reasonable) and big dynamic range. This is as much overall sensor IQ as one can cram into a hikeable package. I'm not sure that even 3 year old 50 MP cropped medium format sensor in the Hasselblad and the GFX 50 line is a meaningful upgrade (the 100 MP sensor coming out in the GFX 100 almost certainly will be, but that's at least twice the system weight, not to mention three times the cost.
2.) Weather sealing/durability. I haven't seen anyone refute Nikon's claims that it's a D850 from a durability and sealing standpoint, and I've seen a lot of support for those claims. That's at least in the same range as the top Fujis (X-H1 and medium format), and well beyond any Sony (even the A9 has unsealed points) or the EOS R (which Canon explicitly refers to as in the 6D Mark II class, which translates into Nikonese as "kind of like the D610 or the D7500" - D850 in Canonish is "somewhere between a 5D mk IV and a 1Dx mkII"). The only mirrorless camera that might be more resistant to the dust, mist, etc. of long-hike landscape photography is an E-M1 mk II (add DSLRs and you can add a couple of top Pentaxes, plus the D5 and the 1 Dx mk II (and their predecessors). The E-M1 mk II would mean going from the very top of the range in image quality I can realistically carry to the bottom of that range. A pro sports DSLR is outside of the realistic weight range for me to hike with and into the GFX 100S weight range (if I were to carry anything that heavy, it wouldn't be a 9 FPS 20ish MP DSLR, it would be a 100 MP camera!).
3.) Lens roadmap. Apart from the NOCT, the initial Nikon lenses make sense for what I want to do - very high quality for modest size and weight (sacrificing aperture). The 14-30 is due next year, and a 14-30/24-70 kit is about as good as it gets for long hikes up to hundreds of miles (the only other thing I might want is a macro lens - long lenses are useful, but not carryable - and, unfortunately, that's physics). The very solid FTZ adapter invites the possibility of anything from a very long lens (theoretically up to a 1200-1700mm if I had the money to buy it and the artillery mount to handle it) to a tilt/shift lens for use closer to the car.
4.)Ergonomics. It really does handle like a nice DSLR - different from a Fuji, but also nice.
Why not (in rough order of how close it came to the (nearly) final decision to add Nikon Z to my Fuji system):
1.) Stick with Fuji APS-C only? I'm certainly planning on keeping my Fuji system - I have lenses Nikon doesn't yet make for the Z, and I can also assemble an even lighter one-lens kit for when mobility is absolutely paramount (X-T2 plus little 18-55)... 46 MP with two extra stops of DR at certain ISOs (that I like to shoot at) is pretty irresistible, though.
2.) Add Fuji MF, since I already know and like Fuji? This got very serious consideration, and was, in fact, the option that came closest... What I looked at the hardest was the GFX 50R, which is the most hikeable form of Fuji MF. The lenses are big, even if the GFX 50 R body isn't huge (the "not here yet" 40mm near-pancake might be the exception) . The lack of any kind of IS on most lenses is a serious drawback to me. Image quality is very close - I used the Imaging Resource comparometer test, because it's the only thing that gives the exact same shot on two cameras, and the differences are tiny (generally favoring the Fuji, but by so little that it could easily just be Fuji's superior JPEG engine or a minor difference in lens quality). I'm sure the GFX 100S will be in a different class, and it has stabilization, but that's also in a completely different weight and price class.
3.) Look at Sony? Weather sealing - see the imaging resource test, where the Sony does much less well than just about anything else... Ergonomics - I've shot a lot of Sonys, and they always feel (to me) like computers with lenses instead of cameras with digital hardware in them. Lenses - The Nikkors seem to be superior to anything Sony makes in a comparable size and weight range - the 24-70 G-Master may very well be as good or better than the little Nikkor zoom, but it's twice as heavy, and the 24-70 "Zeiss" doesn't seem close to the Nikkor. Sony certainly has a lot of appeal to someone looking for a wider native lens range (I'm really looking for two native zooms for the majority of my work (standard and wide)), or more bodies to choose from.
4.) Think about Canon? 30 MP doesn't seem worth the jump from 24 MP Fuji, especially when it might actually cost me dynamic range. The initial lenses don't appeal to me as much - I suspect this would be very different if I were a portrait photographer salivating over fast apertures and not minding a little weight. I haven't handled one myself (and it doesn't seem close enough that I feel like I need to, although I'll certainly take a look before handing over the $ for the Nikon if the shop where I'm on the Nikon list has one). No IBIS is a disadvantage, although the most hikeable lens does have lens IS (and knowing Canon's reputation for lens IS, it's likely to be very good). No roadmap for a native wide-angle, which is the second lens I'd want (although I like the little bit of extra reach on the 24-105). Many initial reviews don't love the ergonomics (somewhere in between Sony and Nikon/Fuji), especially the touch bar.
5.) Wait for Panasonic? Big bodies and lenses without the benefit of medium format. I can't see the sensor being any better than the Nikon/Sony sensor, because it's none of:
a.) medium format
b.) 16-bit
c.) significantly higher resolution.
The 46 MP Nikon sensor (and its close cousin the 42.4 MP Sony sensor) are pushing the limits of what's technically possible for a ~45MP, 24x36mm, 14-bit Bayer sensor pretty darned hard. They have useful data in the final bit of the ADC at base ISO (so any more DR would require a 15 or 16 bit readout), they're getting very close to the theoretical limit of their resolution at low ISOs, and their color depth is as good as Bayer's going to get. It may not be possible to improve on that sensor (at least not very much) within its basic parameters - and the Panny sensor doesn't break through any of those parameters. If it were 16-bit, it certainly could have more DR. If it were well above 50 MP, it could resolve better (it might take 60 MP to see it in a print). If it were medium format, it could have different bokeh. If it were a Foveon, it could have different color in a way that can't be adjusted with a camera profile. But it's none of those things - it's another ~45 MP 14-bit full-frame Bayer sensor, and it's constrained by the theoretical limits of such a sensor, which the Nikon and the Sony are very close to reaching.
What the Panasonic could very well have is significantly different (better) video - I'm almost expecting it, but I'm not willing to pay the weight for it... Someone who's more of a hybrid still-video shooter may well want the better video.
They're all appealing to different photographers, especially when Canon gets a body worthy of the 28-70 f2 and 50 f1.2 out there, but Nikon (plus my existing Fuji APS-C) is my choice for those reasons...
Dan