It's kinda dramatic and thrilling. Also, it is very clever and not dumb like most thrillers where the characters succeed because of the toys or backing they have or because the author needs them to succeed, in order for the plot to move. In C-Blossom, the characters move or succeed simply because they have the motivations, the urge, a goal or some other reason to survive.
Also, it has quite a few exciting and interesting moments within the plot and both the artwork and writing are quite adept at capturing the various characters' moods and thoughts, as well as the tension between the cast. The chase and explosion scenes were also not too bad and actually quite thrilling.
However, I'm not sure if this is because it was an adaption from another series or because it was poor plotting on its' part, but some of the moments within the story are kinda lacking. As in... there is little reference to moments which somehow share an important connection to critical parts of the plot like the rivalry between the 2 team members, who now work for opposing sides. Basically, at times, it feels like you're just reading scenes that are referring to another manga instead of flashbacks that actually inform the readers about the relationships, reasons and moments for the characters' behaviour.
Also, some of the action scenes are a little choppy in their deliverance and it feels like they were often too short and could have done a bit more detailing.
However, those points aside, the story was fairly enjoyable and interesting because there are few titles that actually make you feel like you're experiencing a REAL thriller instead of feeling that the title was crafted just so it could fit the "thriller" category. This extends to all genres: shoujo, josei, shounen, seinen, yuri, yaoi, etc., etc. btw. There just aren't too many I could even call a thriller because they tend to be over-dramatic, overtly contrived or extremely convoluted stories that just aren't well-plotted enough to capture the tension of the action, or even the twists of the story. And for this story, I just couldn't stop reading because it was really just that good! Just as you thought that things were what they seemed, everything takes a twist or two and then later, a certain situation evolves into something else entirely.
Also, I liked the main female character because she's determined and neither weak nor overtly strong, thus being a suitable complement for Kou who's supposed to play as the "protector" of her. I also liked his rival whose feelings could be easily understood. All of the characters moved very well within the plot and their thoughts, gestures, etc. matched up perfectly with their personalities.
And I know these are Seinen recommendations but those who want to try some other thrillers might wanna give Confession (KAWAGUCHI Kaiji) or Seizon - Life a shot. Also, someone needs to do Boukoku no Aegis too! 🙁