[CharlesW]

The iPhone XS is 13mm wider. You can absolutely use it one-handed, and can enable Reachability[1] to make one-handed use easier.

[1] https://9to5mac.com/2017/11/20/iphone-x-how-to-enable-reacha...

[graeme]

Reachability is annoying. Also the X is heavy. I find I get picky strain if I use one for a while.