You've got better than, but you have to remember that consoles are built around playing games only and all of their resources are used for just that, not running the heavy multi-tasking, resource-intensive OS that PCs have. That being said, AC4, for example, on your PC with the correct settings should look better than AC4 on the PS4.
That being said, whether or not you should buy one is up to you. Would you likely want to play a lot of the PS4- or console-exclusives? If so, then yes go buy one. If PC gaming is enough, and you won't be tempted by games like I was by Last of Us (I bought a PS3 just for that) then don't buy a PS4.