Just echoing some opinions in this thread as an owner of both (well I have a laptop I use for games).
Buy a PC.
If you have numerous friends with a PS4, then by all means buy a PS4 then it'll be fun, but as someone with no friends: I've only played on the Ps4 for the Cod: WW2 story and that's it (I haven't even finished it jfl).
PC can run majority of the games which a ps4 can and as others have said, it won't get outdated as you can just buy small upgrades here and there.
The only downside to a PC is the initial start up cost.
Let's not kid ourselves, if you want a VERY GOOD pc capable of running games at 60FPS at a high graphics setting you're looking at £800 or so (minimum).
The playstation can be bought as a bundle for about £250.
That's why majority buy ps4's because they can't afford to drop £1000+ in one go on a pc, but can afford to gradually drop money.