Just finished looking through RAW sample files I've downloaded off reviewer websites from X-T3, X-T4 and X-S10 (since it's the same sensor with the same processor). I mainly focused on high contrast, high ISO or low light images to see how far the files can be pushed. The editor I used is Adobe Lightroom Classic CC version 11.2
*I love the colours, they are very pleasant and warm
*The White Balance seems to be quite pleasant as well, not too warm or too cold (though I do tend to prefer on the warmer side)
*Virtually no Chroma noise !!! ... that just blows my socks off because I am so "tired" of seeing it on Micro Four Thirds but even 35mm FF (I get colour noise on my a7R II at ISO 100 if I push shadows)
*The Luminance noise is very pleasant on smooth backgrounds like the sky, it haves a very "film" look to them, which I quite like
*The Highlight recovery is quite good, at least 1 stop, possibly 2 stops if slightly underexpose, the blue colour in the sky is maintained in most pictures I tried
*The Shadow recovery is very good, at lower ISO I managed to push it 3 stops with no issues, at higher ISO it's a bit more complicated (explained in The bad)
*The files are quite responsive on my laptop (Intel i7 9770H, 16GB DDR4, RTX 2060 75W TDP with no MUX integrated)
*While Luminance noise looks quite pleasant I don't think/see it any better than Micro Four Thirds and not as good as Sony a7R II
*ISO 6.400 is VERY ROUGH, I mean pushing the shadows just adds no details or useful information to the image (it's just better to leave the shadows dark)
*ISO 12.800 is not particularly useful if there's fine texture/details because they are just scrambled (like grass, text, bricks, leaves, etc)
*There is a difference in the level of details between 26 MegaPickleRicks (I NEED TO TRADEMARK THIS TERM FOR T-SHIRT) and 42, by which I mean I am not seeing as many details even at ISO 160 as I would have liked ... BUT \/
*The samples I found were tested with the Fujifilm XF 18-55mm f 2.8-4 R LM OIS and I don't think this lens is a particularly sharp lens, which might have skewed my perception of sharpness and details in the images
*The foliage rendition seems to be a bit off at times, like details on the leaves are missing or leaves altogether blending with each other on the wider angle images.
Overall I am losing some of the initial excitement about the Fujifilm option because at above ISO 3.200 there seems to be very close to the older 20 MP Micro Four Thirds sensors (or more like the OM-1 sensor has caught up to Fujifilm in terms of high ISO rendition and editing resilience) and mind you the Fujifilm sensor was BSI type before OM-1s. And that makes it more difficult to accept the awesome no Chroma noise advantage because Fujifilm had f 4 to f 5.6 maximum aperture on telephoto lenses with the only exception of Fujifilm XF 200mm f 2 R LM OIS WR (which is bloody expensive compared to Panasonic Leica 200mm f 2.8 Power OIS and Olympus 300mm f 4 Pro Sync IS).
Put those 2 together and I honestly think Micro Four Thirds will give (wildlife photographers) a similar IQ with less weight, smaller size and cheaper price.
But I don't think both can compete with (my current situation/decision) camera, Sony a7R II for image quality. (Though it can be easily argued and I would full-heartedly agree that for a non-professional my Sony a7R II and 35mm FF is overkill). At the moment I am left just time to wait and keep shooting and think more about what I should do.
One nice thing that happened a few days ago is I have read rumours about Tamron releasing a 150-400mm f 2.8-5.6 lens for E/FE mount. Could be a nice companion to a Tamron 28-200mm f 2.8-5.6 and if it's not too big or heavy an alternative to their 150-500mm f 5-6.7? (But annoyingly the rumour also mentioned a 45mm f 1.4 and 90mm f 1.8 lens for DSLR ... why? Just make them for mirrorless cameras too?)
I may explore the idea of Sigma 28-70mm f 2.8 and Sigma 100-400mm f 5-6.3 combo to keep the size and weight down.