What's the "killer app" of the PS4? Apart from exclusives, both seem similar. Both seem to be considerably worse as a media box compared to the good old 360 with it's magnificent built-in DLNA compatibility and CD-ripping.
It seemed to me that Sony invested a lot more than Microsoft in making games during the PS4 era. Microsoft seemed to think Gears of War and Halo were "good enough" while Sony was producing a lot more exclusives. Microsoft must have realized they were getting slaughtered due to lack of games since they started buying gaming studios towards the end of this era.
It also had very strob library of exclusives. If somebody told me I’ll spend 400h in front of TV playing souls game I would’ve laughted them off, but Bloodborne did it. They also had other strong titles like Uncharted, Horizon, Last of Us.
All of the Xbox One's benefits mainly came later when they added backwards compatibility, 4K Blu-ray support, Game Pass etc.
At least for some gamers that I know: PlayStation VR