If you're looking for a simple manga without any unnecessary complications, look somewhere else.

Plot (8)
When you read the synopsis first, you may think it's pretty simple, but it totally complicated. The story focuses on the dark side of life: Death, orphanhood, lonliness, crimes and more. You will see unmoral actions (which will influence some of the characters. Even a character who doesn't look hurmful at the beginning, may reveal its darker side).
The story in the beginning pulls to certain direction, and as it goes on, the relationships are changing as well as the feeling of the characters (and even their mental condition).

Characters (8)
In one word: tragic. Most of the characters lost someone who is important to them. You can see the first death in the very first chapter! The death in each of the character's life is going to change their lives forever. There are also the charcters who were unfortunate from an early stage of their lives. The charcters can make you angry and also make you sympathize with them.
Most of the characters go through a change in a certain point, and this will be a point of no return (they will never be as they were before).

Art (9)
There are better, but it's really really good.

Enjoyment (8)
I enjoyed, but in certain points it started to be confusing and really irritating (but maybe the things that made me angry, will make others happy. It's very individual)