I watched the anime, but I didn't read the manga, so here is my review:

Story: 9
The story is really good, and people who watched the anime will not be disappointed. The ending (no spoilers) is a little different than the one in the anime, but still worth it. It's a story with good characters, and a envolving plot. I don't give it a 10 because there are some minor plot holes, but nothing that will affect the main story.

Cast: 8
Some of them were really good, and some didn't convince me. But it's still watchable.

Music: 10
The music is really good, it suited well with the series.

Rewatch Value: 10
Yeah, I would definitely watch it again.

I also want to say the photography and sceneries are amazing. They did a really good job! It's a good J-drama, it has been some time that I watched one so good.