I recommend to wait at least for Q4 2017 when vr market will grow fat, currently there is oculus and vive, both quite overpriced, once other big competitors release their headsets prices will drop and vive will release htc vive2 to save position in the market. The only thing worth buying in vr world in case you already have ps4 currently is PS VR which is pretty cheap (399$ comparing to $600 oculus and $800 vive), as bonus you can connect ps vr headset to your PC (it'll emulate work of oculus)
Why not oculus or vive?
1. There is not much soft except some demos, you gotta wait as big devs only beginning to optimize their games for vr, as currently happening with asseto corsa or fallout4
2. Setting up vive vr room is pain in the ass. And oculus didnt even have that stuff with tracking in 360 or controllers (they just put xbox controller) like vive , until they released oculus touch (shit you have to buy in addition to your oculus rift, to get simillar expirience that you get from vive directly out of the box, which makes overall price even higher and setup even harder comparing to vive
3. price. 800$. We're not talking about shit like google cardboard now, which isnt really a "virtual reality" thing, it just lets you watch stuff in 360 degrees without tracking
talking about porn, the situation here is the same. people made some 360 porn videos, but you don't need a vive or oculus to watch it, 2$ google cardboard (or better alternative) is enough. Sure, It'll be the next level of porn comparing to experience you get from monitor, but its far away from real VR too. Future of VR porn - games, as they're the only thing that can use benefits of tracking, thing that makes VR so believable. That's it, "Summer Lesson" is currently the game with biggest sales on Playstation VR. What this game is.. is just dating simulator with anime girls in it