How do you like the X100 in comparison to the X100T?
It feels very good, very good indeed.
Let's note right away that I sold the X100T in 2017 so my memories of it are fading. Moreover, back then I had a different focus in photography than I do, today. Back in 2016-2017 the little camera was my primary shooter and it was only replaced by the Leica Q.
Let's say the X100T is a 500 € camera, give or take. The X100 has been valued around 200 € for a while. I got mine for 175 €.
Autofocus: both are equally terrible in so that you rely on single-point S-AF to get anywhere, can't rely on much else. The X100T focused in pitch black conditions much better than Leica Q (another CDAF focuser), so I think it would win in single-point S-AF against X100 handily by a great margin. The software upgrades or sensor improvements can't fix the slow focus mechanism of the lens itself.
Screens and EVF. X100T is a clear winner. X100 has a poor EVF that lags and jitters a lot when the light levels drop. It's good for my use case -- it really encourages to fully push for the OVF. The camera software is very good and operation with regards to EVF/OVF is quick. You can be in OVF all the time, but press this one button to check your focus in a magnified view, and you're then back to the optical view in no time. It all works out quickly and seamlessly. Kind of hard to believe it's ten year old tech.
Build: X100T was one of the best experiences in this regard. The buttons in particular felt so nice. X100 feels very rough on the edges in comparison, and the buttons on the back are notoriously bad.
Software: Decent on both, with all the firmware fixes done in. X100T has much more customizability like we know Fuji for, whereas the X100 only allows to adjust two of the buttons and that's it. X100 has all different, modern-feeling niceties here and there, like highlight blinkies, but they can't be adjusted in playback modes to one's taste like you can with the newer Fujis.
Lens: same design I suppose, but the aperture blades make much noise on this original X100.
Sensor. Everybody raved about the wonderful sensor of X100, and it really is a wonderful pairing, the lens and the 12 MP chip. I like this sensor a lot and I don't like the 16 MP X-Trans chip of X100T much at all.
JPEGs. Haven't shot them. I am under the impression that Fuji has tweaked the colors throughout the generations, always inching towards "maturity" or subtlety. The colors on X100T were also very "candy-like". Classic Chrome used to be my favorite. But all those Velvia JPEGs I took with the X100T now look like crap, with no raw files to be found. That's why it's raws for me. Speaking of...
Raws. Beautiful noise structure (although all I've shot so far have been at base ISO) on the X100. And while I want to avoid rekindling the war that was the Bayer-v-XTrans, I am solidly on team Bayer.
Fill flash. Both models excel at fill flash and automatically metering a good balance. This is the main reason why Ken Rockwell titled the X100T the world's best camera. Its fill flash works wonders and makes subjects pop. Of course you need enough ambiance light for it to be "fill" flash. Using the camera's builtin direct flash in dark conditions will continue to look poor.
Other tidbits. X100T introduced the Electronic shutter option so that you didn't really always have to consider the builtin ND filter. I certainly didn't bother with it. Does X100V have an option to enable the ND filter automatically when needed?
Performance. Card writing times on the old X100: can't complain. Very good indeed. Playback is also very smooth and quick, considering how people all claim it's a slow camera in all operations. With the latest firmware version 2.11 from 2015, I can't agree. It's way more fluent than expected.
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So would I consider an X100F at around 700 €, an X100T at 500 €, compared to this ~200 € X100? Not really. The price is a factor of sorts. I get much satisfaction getting my hands on a nice looking tool that punches well above its age, and how affordable it can be!