I have a PS4. Currently playing Far Cry 4, which is quite entertaining, but also bastard hard (I suck at games though, despite making them for a living).
Before that I played Last of Us Remastered (after owning the PS3 version but for some reason not playing it for 12 months). One of the best games I've played in years, stunning character art, good story and intelligent level design. Environments start off ropey but get better and better. It's probably the best PS4 exclusive out there so definitely play it if you haven't (probably don't bother if you played the PS3 version though, it's not that different, probably just 1080p rather than 720p).
Other than that there are a pretty disappointing range of PS4 exclusives at the moment, almost wish I'd bought an xbone, I could be playing Sunset Overdrive right now. Gotta remain loyal to the brand though, don't bite the hand that feeds me etc. Might pick up Little Big Planet 3 next week