Well, I'm returning my X100F due to squishy screen and some EVF problems. I basically decided to go for a used X100T. However, upon further tests, I simply can't go back to X100T... F might look like a minor upgrade from the outside, but I tell you - it's a SIGNIFICANT upgrade over the T :
1. Sensor. I still can't believe these new sensors resolve at 24 megapixels. I remember getting original X100 and I was like : "Man, 12 is enough!".
2. High ISO. I would never push old X-Trans II beyond 3200 ISO because of waxy skin tones(even at 3200). I can easily push my X-Pro 2 up to 8000 with no problem. Even 12800 is quite usable(for my taste).
3. New processor = speed. F is VERY FAST. Startup time is WHAAAAAM!
4. AF upgrades. F focuses faster than X-Pro2 with 23mm 1.4. I don't have 23 f2 to try, but I have 35 f2 and it's barely behind. Continuous autofocus is dramatically improved! It's USABLE NOW!
5. Button layout and ergonomics. I'm not a fan of ISO dial on the top, but the fact that it can be assigned to front command dial is a no-brainer. I read that a lot of people find AFL button placement awkward, but it's perfect for my taste - it's right where I place my thumb. Joystick is another no-brainer. F is highly customizable. SO MANY FUNCTIONS TO CHOOSE FROM!
6. ACROS! If you shoot b&w this might be the solemn reason to upgrade. If you might not know, in-camera RAW processing of acros is much different that one in Lightroom. I usually import acros jpegs into Lightroom to do some minor tweaking. It's very, very good b&w simulation. I will probably end up shooting it for 80% of the time.
Well, these are 6 major improvements for me. If you're willing to pay $100 for each, then you can easily justify upgrading from X100T.