I’d get the 8+ for that exceptional battery ! But, the X has a great feel (& heft, imo) and that swipe up to close apps is a killer feature!
I have to charge my X around noon every work day, but could easily go thru the entire day with around 20% or more remaining on the 8+. It may sound trivial, but having to recharge at mid day has been a real PITA! Now, I just keep the damn thing on a wireless charger at my desk!
I also find typing easier on the 8+. Face ID is great, but touch ID is better imo.
Aesthetically, I like the X and the 8+ for functionality.
Having said that, the X is very good, but if HAD to just stick with one...it’d be the 8+