This is one series of somewhat intertwined short stories that is often overlooked by one of my favorite manga-ka, Mohiro Kitoh.
As short stories, I think it highlights Kitoh's best storytelling ability. Much like with Bokurano, I find that he has a natural ability to build upon the themes with each subsequent story, without needing to worry about continuity. Each is its own look at cruelty, sacrifice, and futility. Each also filled with its own philosophical problems dealing with these winged dolls. The basic theme being, that although they are real and seem to express thought and emotion, they are also creations and possessions.
Much like Kitoh's other works, it is not written for everyone. It is particularly tame compared to his other works (mostly because most of the abuse is directed towards dolls, and stays away from the child sex and child abuse like his other series). But many of its themes still remain just as dark and cold. And probably may still offend.
You don't necessarily have to agree with it, but if you take a step back and look at the messages he is trying to convey, and his way of telling them, then you can see the underlying beauty in the cruelty of the series.