Have put 20 hours into this since owning it...absolutely love it, even if I have a few gripes. For one, I wish the DLC had previews of the songs though, I end up looking them up on YouTube to see if they appeal...
I've actually only unlocked one character (Cid). Eight shards for each character seems a bit much, but it does keep me going at unlocking new dark notes. I've gotten really sick of that vocal song from FFXIII
This game also motivated me to buy IX for my PSP! Sadly the system doesn't want to work with my current router, so I have to wait a while until I can play it
it's amazing how much Theatrhythm gets you in the FF mood though, I'm itching to finish off a few enteies that I haven't finished because of it.