To those in the dark or on total FFXV media blackout, SE released FFXV Judgement Disc Demo on 11.11.2016 exclusive to Japan. The demo runs on the latest build, and what players can more or less expect on Day 1.
Keep in mind, PS4 Pro version will receive an additional patch in December to further optimize support (higher framerate, developers aiming for stable 60 fps). The demo does include a degree of PS4 support such as High Quality Mode to increase visual details.
After 10 years, the game will finally be out. So feel free to watch the video and determine which system you wish to play on.