Not really played it to be honest. Been playing AC4 and NFS mostly. Will probably only move over to KZ once I have finished AC4.
Of the three games I think KZ is the better looking as it was obviously designed solely for the next gen PS4 whereas the other two are across all platforms, so more than likely didnt have as much attention to graphics. Although that said, both AC4 and NFS are incredibly beautiful looking games.

I must admit what I have played of KZ was a bit underwhelming, but thats because you start off as a small kid with no weapons n shit.