The X has been a surprise for me.
Positive:
I thought FaceID would be worse than TouchID. It's better, so far. It's just as fast or faster in almost every scenario I've thrown at it. It's like not having any passcode or lock on. If they implement a direct unlock to home screen without the upsweep it will absolutely kill TouchID.
I thought the notch would be a problem, but it's really not bad. Definitely not preferred, but I hardly notice any more. Even in videos in landscape.
I don't miss the Home Button one bit. All the new swiping gestures are excellent (maybe except for the app switcher, which takes a little thinking to get right). Adios Home Button and TouchID. The UpSwipe to home is the way to navigate iOS.
Negatives:
The OLED has been a major letdown. I was expecting a major upgrade from my 7 Plus, but all my family and friends (including myself) say the LED panel on the 7 Plus is brighter, whiter, and just plain looks better. This includes the tech savvy, and the clueless (my mom). I have several X units here, and they are all yellow, with slightly different tones. (please don't @ me about how this is intentional color calibration nonsense. All the panels are different. No it is not true tone. I turn that nonsense off).
Comparing videos side by side, browsing apps/websites, I choose the 7 Plus every time in all lighting conditions. I can't believe this was the hype over OLED. Yes, blacks are blacker, but I'm not even sure that is a bonus as you lose contrast between many different shades of black and it just looks like one blob. I forget the term, but there is a setting on my TV to try to address this.
The size is a disappointment coming from a 7 Plus. I went from the iPhone 5 to the 6 Plus, to the 7 Plus, and my first impression of the X was that I was back on a 5. The Plus models made you feel like you could live without your iPad, because it was more a mini phablet than a phone, but the X is like the 5: it is a phone. It's not something I want to browse websites on. If you are coming from a 4.7'' screen, it's probably a nice upgrade. But as a Plus user, that little bit of width lost drastically affects the overall feel. The height added does not make the phone feel bigger. And you do not get more content in most circumstances.
Overall, the X is great in all the things I expected to be bad, but crucially misses in the parts I expected to be good.
If they had an X Plus, with a better OELD/LED panel, I would have gone crazy over it. I would prefer an X Plus with LED panel, and knock a few hundred dollars off the price of the phone.
As of now, I'm considering just keeping my 7 Plus. I'll most likely keep the X to be on the latest, but this is a consideration I didn't think I would have to make.