Regarding the iPhone X vs previous models, so far I prefer TouchID to FaceID.
TouchID is something I learned to forget about. I trained multiple fingers on it, so even if the phone was lying flat on a desk and not facing me face, my finger successfully unlocked the phone without me thinking about it at all. Now, in that flat on the table position, my phone requires my code because my face is not within view. That takes a lot longer.
I like everything else about the iPhone X, especially the battery life and better use of screen real estate. The absolute best new feature is wireless charging (not new to Android, but new it iPhone), but you can also get that on the iPhone 8.
FaceID works great when your face is in view. It’s every bit as convenient as TouchID 90% of the time, but I do notice that 10% when I’m not looking at the phone directly when I unlock it.
Two steps forward, one step back. Do you agree?