The story is not original. Period. But if you are the type of person who likes shoujo/slice of life/ cute girls/ fulfilling dream anime, watch this one. The story progressively gets better, a bit boring at first, but after....oops almost gave something away. Just trust me when I say it gets better.
The art was pretty good (I have high stardards, if I don't like the art, I don't watch it). They could have worked on the 3-D part a bit more though.
I would've given the music/sound a 10/10, but the beginning music was too repetitive. In fact, the beginning episodes in general was repetitive. The background music, their show music, is all incredible though.
I've met many characters like the main characters in this story in other anime/mangas, but that didn't stop me from loving them. Some of the supporting characters, like Kaname and Rhythm's mother, make the story more interesting for me.
Again, I would have given this full points if it weren't for the repetitive-ness of the beginning episodes. Other than that, it was thoroughly enjoyable. I had my eyes flued to the screen for the last few episodes.
I like it. It may not be original, but at least it kept me wanting more, and I enjoyed it. And that's all that matters.
Remember, this is just my own opinion. You are completely entitled to your own and don't have to agree with me.