if you have the ability to choose between the two, I'd go with the X. FaceID works just as well as TouchID, you get a slightly better camera (the only difference is the X as OS in both the wide angle and zoom lenses whereas the 8+ only has OS in the wide), and smaller body but larger screen. However, Apple's phone cycles typically start in september of each year so there's just a few more months until the newest X is unveiled and up for preorder if you can wait as an FYI