This was quite nice to read in one reading. Some parts of this were cliche and stereotypical, but overall, the book was a pretty entertaining read.
I might see if I can access more volumes of the series online, since my library is closed right now, so it was kind enough to make me want to read more.
If you liked death note, I feel like this discusses similar themes, with what justice means and who is allowed to carry out that justice and morals and stuff like that. That's the parts of the book anyway that I found the most compelling.
I have to say that I was expecting something very different when I picked this book up: code breaker is in the title, so I was expecting more of a hacker or spy situation. I also have to say that the name code: breaker doesn't make sense, since it has nothing to do with the whole premise of the book. May be explained in later volumes, though?
I was also very frustrated with the whole teenage drama that was going on in the book too. Like, I wish that Sakura's friends would just knock it off and act more mature.
That is to say: this book was good, but not great—purely middle of the road for me.