Hello,

I would like to share my experience about recently acquiring and using a Sony A7cII camera after having used Fuji-X gear for the last 10 years (and also MFT from 2013 to 2019).
I originally chose Fuji-X because I could get very good IQ in a small package, using mainly small prime lenses such as Fuji 23 f/1.4, 35 f/1.4 and 56 f/1.2. This was a strong benefit for me, especially early on about 5-10 years ago.

Today however, the situation is quite different. Small Fuji bodies such as the X-Txx and X-Exx series do not feature in-body stabilization and the viewfinders (IBIS) are the smallest in the industry. The X-Sxx series features IBIS, but the viewfinder is equally small. Recent Fuji lenses have inflated a lot to the point that I don't really see any benefits from the APS-C sensor size anymore. It's even more true of Fuji zooms.
If you actually compare equivalent systems between Fuji-X and Sony FE with a body like the A7cII, the more compact equivalent system is often the Sony fullframe, hence my motivation to switch. Furthermore, lenses for Sony FE can be had for much cheaper. The Sony body is more expensive, but the lowest price of lenses makes up for it. Also, if you value depth of field control, the Sony is clearly more interesting as you can purchase affordable f1.8 lenses which have an equivalent depth of field of f1.2 on APS-C which is available only for a couple of primes.
If we consider zooms, the Sony is even more interesting. Tons of choices of fast f2.8 zooms at very affordable prices with high image quality and unique offerings not found in Fuji land (such as Tamron 17-50, Tamron 28-200, Sony 20-70, Tamron 35-150, etc.).
When you realize that with Sony, a Tamron 28-75 f2.8 would be equivalent to a 18-49 f1.8 on Fuji-X, which doesn't exist, and for $800, the choice is not very difficult.

Another reason for looking at Sony FE, was the following frustrations:

lack of AF reliability during "action" shots (still) and when shooting videos
the lack of good, affordable, but not huge Fuji zooms and to a certain extend:
the lack of good quality affordable lenses, whether fast primes or zooms
the lack of good quality compact lenses, whether zooms or fast primes

When considering equivalent systems (in terms of field of view and depth of field), Fuji is really not that interesting in terms of cost and overall bulk compared to Sony FE.

Very recently, I purchased a Sony A7cII with the 28-60 kit lens and an additionnal Tamron 28-200. After having used it for a couple of weeks, I have to say I'm very impressed!
The picture quality I get from the "lowly" 28-60 is incredible for the lens size. Pretty much sharp over the whole frame and the lens is tiny, even for APS-C standard. The images I get from the Tamron 28-200 are better than I'd have thought possible. It's really good at all focal lengths, even the corners are descent. Impressive. In APS-C land, it would be equivalent to a 18-131 f1.8-3.7. If Fuji were to make such a lens, I think it would be larger, heavier and not as good optically. Take a look at the current Fuji 18-135 for instance. Sure it's an older design, but I used to have the Fuji 16-80 f4 and sold it because besides the center it was never really sharp.

In term of AF on the A7cII, the ability to use the "AF-ON" button on a subject and recompose works wonders. The AF sticks like crazy to the target (whether it moves or not and whether I pan around). Consequently, there is absolutely no need to move the AF point! Face detection is very reliable, even on small faces. On my Fujis, I never used it because it was not reliable enough, unless for close-ups (and the metering changes depending on whether it detects a face or not which is immensly annoying).
I'm still amazed at how well the AF works on the Sony. It's so liberating to not have to manually fiddle with AF points over the frame. The same goes with video: AF is so reliable and sticky it's amazing! That's definitely a revelation for me.
I was expecting bad ergonomics and operations, but it's actually pretty good given the size of the camera and the ability to customize the menu when pressing the "Fn" button is very convenient.

Finally, one word about jpegs. Fuji has awesome film simulations when you're lazy and don't want to convert from RAW. I particularily like Classic Chrome. Sony doesn't have similar pleasing jpeg already available.
However, Picture Profile gives the jpeg output a level of customization unmatched by Fuji which I was surprised about. It's daunting and not exactly user-friendly, but I found someone who actually provides (for $40) many film simulations that can be configured in camera and that mimic some of Fuji outputs: https://www.veresdenialex.com/sony-film-simulation-recipes
It works really well and I found some that I find very pleasing.

All in all, I'm very very happy with the camera and I think I'll sell most of my Fuji gear (maybe just keep 1 body and a couple of small primes) to fund addtionnal Sony FE lenses!