For me, I think I like the dynamics of the music more than the individual pieces themselves. Like how the Chocobo theme is bouncy and enrgetic when you're running but if you start walking it becomes a nice simple piccolo theme. I also like how the battle theme is different depending on what you are fighting, so the theme is different if you're fighting imperial troops over common monsters, or random daemons versus Mark Hunt battles. I feel FFXV's dynamic use of its music is easily its greatest strength.

With that said, I'm not exactly coming away from the game humming the melody of a particular song and the action-RPG nature of the game makes it difficult to focus and appreciate the battle themes since you're kind of more focused on not getting mauled to death. So it's been fairly hard for me to really appreciate the music of the game. I think the only pieces that stick to me have been the small town themes and Chocobo themes but both are done in a style of music I'm not terribly fond of so I'm not really feeling the OST of this one.

On the other hand, the other Prelude theme in the game is seriously nice.