Well I've been reading along. I am not really the Xt4 customer at this time but hey, why not comment. Size vs FF options.......I've had Z6/7 cameras in hand and an XH1 is pretty much the same size as a friend who owns a Z7 can attest, that is until you add a lens. The F2 primes from Fuji obviously win here as I can load an XH or a Pro3 into my winter coat pocket with any of those primes fitted. The FF options are great till you add a lens. The Fuji gives you the option of using small lenses or the larger zooms and primes. A Z Nikon in my coat with a lens? Can't.
I did a test shoot with the Z7 owning friend. We had his Z7, a rental Z6, my XH (no Pro3 released yet) and my D4S Nikon. I shot a portrait of him with each camera from ISO 200 to 25,600 (Fuji to 12,800). We lit the shot with an LED Godox head in a 30 year old Chimera bank.
We used the default for each in LR. The defaults add some NR as ISO's climb it seemed but we left them on for the time being.
The D4S crushed all for noise and crap at hi ISO's. Things got a little rough at ISO 25k but it was an easy cleanup and in the end looked like Extachrome 400 from years past, maybe. The Z6/7 were nearly identical at all ISO's so that was kind of a surprise. The XH1 was a real surprise. Where the D4 had zero color noise in the shadows the Z6/7 had plenty of noise, freakin rainbow of noise and the XH1 barely a hint of color noise. The Fuji looked better at 3200 than the Z6/7.
Again this is the defaults that LR loads in on import. The Fuji wasn't without noise but it was Luminence not so much color.
So that is kind of an overview of that test. For decades I made a living with my cameras and I owned and shot many formats. Back then the large cameras were (not counting 4x5) the medium formats. I also had Nikon and the Leica was the small go everywhere device. Now the Nikon is the large one and the Fuji the small one. The biggest reason I don't yet have a Z Nikon is it can't be small. I already have a Nikon that is large so why have another. Yes I am ignoring the vast difference between a D4S and a Z6 in theory and design. Plus my Z would have that adapter on most of the time making it all even bigger.
Yes there may be less expensive more "feature" packed alternatives to the Fuji line. What good are they if they are large enough I don't take them out of the house enough?
Neil