I'm seeing it a lot on the internet so I'm bringing it here. SE Japan did a survey asking fans about Final Fantasy XV. The 47th question asked if P5 & FFXV came out at the same time, which would you get. Personally (lol) I would get Persona 5 because I'm more into that series than Final Fantasy. Also, realizing this now, that survey might affect when Final Fantasy XV is release and either delay or push up the release date next year.
Source: Siliconera
Source: Siliconera