I love the music in this game. I don't think I have loved the music in a game this much since Nier or Lost Odyssey.
You can listen to the OST here on youtube, I wont post the video links directly myself, as not to be spammy.
I find myself humming a few of the songs as they play in my head quite frequently. Just a little bit ago a co worker (yes I know, shame on me for being on GB at work) asked me what I was humming. I showed her the song on youtube and she is now sitting and listing to the whole OST at her desk.
And I found this while looking to buy the official OST, which is what actually prompted this topic. And I have to say, I disagree completely. The battle music is great, and does not get old after 1,000 battles. Even if I only hear 5-10 seconds of it.