The only thing Sony seems to have talked about is their SSD tech and how its supposed to be a game changer. Loads of people where skeptical but that Unreal demo did a pretty good job at showing what it all means. Series X also has a very fast SSD but Sony's is still twice as fast. I guess we have to wait and see what that means and how big a role Sony's SSD played in getting those visuals from the Unreal demo on screen. Either Sony paid Epic off, or they truly think Sony's SSD is the biggest breakthrough when it comes to next gen hardware.
In order for us to know exactly how much impact the SSD will have we would need to see comparisons of PC and XSX running the same demo and giving the same time and effort for optimization. That demo did nothing to really tell us how much difference Sony SSD makes. Until we see actual games from both companies taking advantage of their hardware we really will not get a clear picture on this front.