Honestly, I wanted to like this manga. I really did. It's foundation seemed promising, dark even, but instead of taking the more realistic ending (which, I admit, would have probably contradicted the "shoujo" label this was given) the author chose instead to supply us with a halfhearted, "everything is awesome now!"
One point I'd like to make, before I talk about the other issues with this manga, is the sheer difficulty I had following the story. It was always jumping around from one thing to the next, with no transition. Also, though this is more of a technical thing, the scanlations weren't the best.
That being said, the below has several spoilers. Proceed with caution.
The biggest problem I had with this manga is the inconsistency. The lighthearted tone of the manga didn't match with the dark premise.
The shinigami only become such after they've committed suicide and Mitsuki has cancer that will eventually kill her if she doesn't undergo treatment.
Despite this, the ending was so sugar coated that I almost got diabetes. They had an explanation for everything, which isn't always good, especially when it comes in the form of deus ex machina.
And the ending... my god, don't get me started on the ending. It makes NO sense with the rest of the story.
It is established at the beginning that Mitsuki has a cancer that is so bad that if she doesn't undergo a surgery, she will die. The surgery is the only surgery that will help her. This surgery involves removing her vocal chords. There is no "lesser" version. Yet, the ending tries to sell us some bullshit about her still being able to sing. Their explanation? "Because she was Full Moon for so long, the cancer couldn't ** get any worse. **" It was already established that the cancer was already bad enough to require surgery. It "not getting any worse" doesn't mean it was better, and certainly doesn't mean that she can somehow have a "lesser" version of a definite surgery.
Takuto is revealed to still be alive, despite being a Shinigami. Because, apparently, you don't really have to be dead to be * dead. * Guess what everyone? ** He's just in a coma! That means that true love wins! What's that? He went through the same surgery that Mitsuki was supposed to go through? He shouldn't be able to talk? Welllll, SHINIGAMI POWER! The two most powerful shinigami DIE (again) to make sure that Takuto can talk! That's so amazing! Sparkles, unicorns, and sunshine everyone! **
So, it is with great pain that I have to give this manga such a low score. It might be great for the readers who love perfect endings, even at the cost of their own brain cells, but for someone like me... I couldn't help but call bullshit, even if I wanted a good ending.