Let's start with the negative aspects:
The music didn't always quite fit, in my opinion. Sounds way too happy, although the story is rather sad.
Second, the character Mio Sanjo was too annoying and her acting was too much at the beginning. Once she showed up, I didn't quite like the scenes in this drama. Towards the end, however, she got better.

Positive aspects:
All the other characters were great. Well acted. I especially liked Kakeru Osagami. He had the coolest scene in this drama. his facial expressions were real and you believed everything he was doing.
The fight scenes were so good and nicely directed. It was so exciting to see those scenes. Definitely one of the coolest scenes in this drama. The friendship of the main characters has been great. And how the story tied up towards the end was really nice.

One of the J-dramas I would recommend at any time. The story is top. the acting seems realistic.