The PlayStation Vita version of the Valkyria: Azure Revolution Early DEMO where you can play the whole prologue of the game available in the Japan PSN for FREE.
It should be noted that you can move the save data file into the final version which release on January 19, 2017.

In the game quality and content, there is no different between the PS4 and the Vita version. You will get the same story, characters, items.