If you switch to the original HTC Vive, the unit will be bulkier than the Rift S and the resolution is lower and SDE is more prominent than ever because of the low resolution and pentile screen. The screen is OLED though so the colors are better but text is much harder to read on the Vive than the Rift S. The lens quality is also worse than the Rift S although use can use the GearVR lens mod to replace the default Vive lens. You gain 10Hz more than the Rift S so things look a tad bit smoother. Initial VR setup on the Vive is not as easy as the Rift S. Rift S controllers are way better ergonomically and have some finger tracking features than Vive wands but you mentioned that you are getting a pair of knuckles soon so you are good. The Vive is an upgrade over the Rift S in terms that you can use IPD adjustment and eye relief adjustment and the Knuckles and also the Wireless Adapter and additional Vive puck trackers and also potentially upgrading the Vive HMD to the Vive Pro, Valve Index, or Pimax HMD but that's about it.