I rarely give tens to mangas. But this one just deserves it! Why? I'm going to tell you:
Monster isn't a tradional manga. It isn't about fighting. I even dare to say it is a 'Love it or hate it'-manga. If you are the type of Naruto and Bleach and looking for that kind of manga, this isn't the manga for you. If you are looking for an intense, well-written manga, I would recommend this certainly for you.
The story is complex and long. Altough it's long, there isn't one single filler. It is all part of the same story. The story is about several characters, whom all have their own background and story. All the characters, you could just find them in real-life. And that is awesome. It all feels real and the flow of the story is... perfect.
The art was fine, although it isn't traditional drawn. Sometimes I thought the art was too unrealistic for the story. Some of the guys had way too big noses and stuff, but it wasn't really bothering though.
I think it is hard to explain what is so perfect about this manga. The story is excellent, I think that is the main thing why I just like it so much. It is complex and intense, just like I said before. You will like the characters and follow their lives troughout the story. Tenma, the main character, goes from place to place and you get a peek into lives of other people. That is done so fantastic and real that you'll just start loving all those good people.
The story is so complex, it left me with quite some questions. It is a manga in which not everything will be explained. You will have to live with that and make conclusion for your own. I didn't like that first, but now I realise it perhaps is just fine. The actions of humans aren't always explained in real-life either....
My conclusion: This manga is perfect for everyone who loves thrillers and tension! The 10 it has gotten from me, well, it just deserves it!