The iOS version doesn't deserve the negative rep it gets. I don't think it would cost $100 to get all of the songs as Unne has said, as I believe that oft-quoted figure also includes all of the optional characters you can buy. Regardless, I've not downloaded any characters as I'm happy with the ones it has - I think there is the main character from FF1-13. What I have done is download a lot of songs and I think I've spent less on that than I would a 3DS game. I don't see a problem with the business model here as I have all of my favourites and haven't paid extra for songs I am not interested in.

For me it's like crack in video game form. Once you start to get SSS rankings you feel like a hero. Stay far, far away from this game! I also think there's something on iOS that you can't do on the 3DS, and that is compose your own scores for songs. I could be wrong and have someone correct me on this though