First of, this is my first MAL review so please, bear with me a little :).
If you're not familiar with the works of Okada-sensei and don't know what to expect from this title, I recommend reading his previous work, Sundome, which is very similar in tone, themes and of course art. If you've read it, do know that the level of perversion shown in Ibitsu is even greater :p.

**Art**
Starting out with art, I think it's a major step-up from Sundome in both character designs and the use of illumination to accentuate mood. All characters are very nicely drawn and each is distinct. Okada-sensei has a very unusual style, especially prevalent among the female cast. He's also very apt at drawing out the subtleties of facial expressions. You may not like the art style, though, as it's fairly bleak, full of contrasts and white space, but that of course adds to the overall mood of the manga.

**Characters**
The cast is fairly small, but because of this each character is convincingly unique with their own humanly real goals and motivations. Interestingly, Okada-sensei doesn't deal in stereotypes so it's difficult to make references to works other than his own. Madoka resembles Kurumi from Sundome in guise, but their dispositions differ slightly. Kakiguchi is in a way similar to Aiba, but his motivations are completely different. Madoka's school friend, Meg is the slightly jealous BFF who admires the main female protagonist, at the same time feels inferior to her. As in to match the tone of the manga, each character is psychologically broken. Kakiguchi is unable to form an intimate relationship with people due to supposed past trauma and prefers onaholes instead of real women, Madoka is a sadist who enjoys and gets aroused by tormenting Kakiguchi, while Tou sensei is perhaps one of the most despicable characters in the series.

**Story (SLIGHT SPOILERS AHEAD!)**
Ibitsu is mostly about the strange relationship between Moritaka Madoka, a 16-year-old high school girl whose parents divorced and are fighting over her custody and a young-looking 22-year-old sex shop clerk, Kakiguchi Keigo. Madoka is disillusioned and has no faith in people other than her best friend, Meg. Meanwhile, Keigo lives a day-to-day non-existence of little importance, but has a dream to make high quality sex dolls. The story picks up when Madoka moves in with Keigo to find sadistic entertainment at his cost, mocking him for not having any sex drive, but their relationship steadily develops into something more meaningful as the story progresses.

**Finale (MASSIVE SPOILERS AHEAD!)**
I know the general rule is to avoid spoilers, but I think my reflections might be valuable to people who read the story and are struggling to understand it fully.

The reason why my score for Ibitsu oscillates between 8 and 9, is because in my opinion the story is not finished. The way the relationship between Madoka and Keigo was developing throughout the manga suggested that it can go either way and the mangaka is not sure himself. There were clear indications that their relationship can finally become mutually romantic as Keigo slowly started opening up to Madoka and she already sacrificed a lot, including her dignity to protect him, demonstrating that she does in fact love him. Honestly, that would've been beautiful and would've made for a truly satisfying conclusion. But there were also moments like their quarrel about the color of the doll's nipples and the time when Madoka noticed that Keigo is fascinated by her not as a mate, but as a model for his doll. In the end, nothing is finished. Keigo doesn't complete his doll (the eyes, among other things are missing) and Madoka dies in a train accident shortly before meeting him. It's a real shame, because the story could've been so much more.