I am loving the taptic engine additions in the X. From scrolling down website drop-down lists & swiping back/forward to navigating music lists within Spotify/Apple Music. I presume it's also available on any iPhone with the Taptic engine, so many others can also appreciate the virtual-physical feedback. Adding that connection between user & device is a positive step in terms of interaction. Talks of keyboard buttons 'feeling' 3-dimensional in future is the next stage.