Before I start, I hope my score doesn't put anyone off from trying out the manga as it is not a bad manga, just not what I expected it to be. However, that is not the sole reason I did not rate it higher (as that would be unreasonable). After reading the positive reviews, I decided to give it a try.

STORY
First, let's talk about the story. I am always a fan of stories that has a greater continuation, an arc, a goal that it is trying to reach in the end. But as mentioned in other comments, it was stated that it is completely episodic (eg. CSI). Although I find the stories very realistic, there are a few problems I have with it. Unlike other crime/ mystery/ police manga, this manga does not have as much detective work. I understand that the MC is supposed to be a good detective and is able to solve cases relatively quickly. But sometimes he does so too quickly. There is no "searching for clues" progress that other crime mangas might have. I just feel that although the stories are realistic, it falls a bit bland and fails to keep me captivated.

ART
I do know this manga is dated, but when it comes to judging art, it is relative. I have a hard time judging art by taking in "time" as one of the explanations. Because i find that sometimes old mangas have really good art vs current manga; hence, I tend to not take time into account. As for the manga, I find that it does the job fine. Everything looks how it is supposed to look. However, I find that the characters' expressions are not as good as I hoped it to be. And there is this weird thing where most of the characters will have weird eyes (like how it would look like when you put a finger between your eyes). And that just takes away a lot of the immersion a manga might have with the "doodly eyes".

CHARACTER
Although all the characters are somewhat believable, I find the MC to be extremely boring. When you have supposedly cool. badass MC's, you would want to know how they became the way they are. You are interested to see will things that happen in the story affect how they are, or show you why they are unaffected by it (often times through flash backs or a pre-established back story). But this manga doesn't really have it. I know I read relatively few chapters, but the other reviews did mention that the manga just shows different cases and doesn't really show you more of his character. And in the few chapters I have read, the MC has at several times make shocking decisions and have questionable values. But it does nothing to explain it, show why he does what he does and how he came to be. This I feel is just wasted potential.

ENJOYMENT
In a story, especially a manga, art, characters and stories are the few elements you have to affect a readers enjoyment. Because of the reasons I have mentioned above, I find myself getting bored rather quickly. Because of it's episodic nature, lack of back stories and development, the story does not feel like anything has changed. And I do understand a lot of mangas, animes, and other shows do this as well. But I do think there is at least a little bit of the things I have mentioned to make them slightly better.

CONCLUSION
Like I said, it's not a bad manga, just to me, it's not a good one. Compared to all the positive reviews that are found here, I wish to be able to give you an insight from a different perspective by playing as the devil's advocate. If you feel that an episodic manga about a bad ass detective and your case-of-the-week without a greater overall arc, backstory or character development is something you are alright with, give it a try. I think that you might enjoy it.