Very good at first, but after some time it losses the "magic"
After getting used to all that beautiful effects and shining cubes, you start thinking that the game is boring and all that wonderful effects losses the initial "magic" of the game.
It's a light game, great for people who don't have a good hardware or are just trying to find a way to pass the time while you are downloading something, or such a great way of competing with friends through a score battle.
I think that this may be a boring game if you don't have a big collection of songs and you really like them to play it almost every day.