Extremely dark and more than a little depressing.
Basically the point of the story is that the main male character has to vicariously deal with all the bad stuff that can possibly happen in life to a woman -- molestation, childhood rape, physical abuse, disassociation, stalking, peer abuse, having your children taken away from you, miscarrage, etc...
By the end of the third volume or so, he's cursing God's name and meaning it simply because of all the agony the women in his life go through.
It's well written, but so painful that it's hard to read more than a little bit in one sitting.
Don't go into it expecting 'Girls Saurus' or 'Donmai Princess', and you'll probably be okay.