I started reading it because it has two crossovers with Hirunaka no Ryuusei, and I absolutely adore HnR. At first, I just kept hoping it would get better, but it never really did.
I'd like that Hatori has bad points more if she had any good points to balance them out. She doesn't, really. I'd enjoy watching her struggle if she learned anything from it, but she doesn't. All she does is think about Rita, or think about trying not to think about Rita. He's her entire world, and it's annoying at best, but just as often it's rather disturbing.
Rita started off okay, but once he started dating Adachi, Hatori starting pushing him, and he turns out to be wishy-washy and spineless, the kind of guy who hurts people because he can't make a decision.
A lot of people seem to dislike Adachi, probably because she's treated like a personification of the Perfect Shoujo Heroine trope. I haven't read to the end yet, so I don't know what happens to her, but I feel like Hatori and Rita are kind of ruining her. Adachi has dreams of her own, beyond being with Rita, and they're just dying.
Nakajima's great, though. If there were a manga with Nakajima as the heroine, I would read it so hard. And Hiromitu's all right.
I'll probably keep reading to the end, simply because I've gotten as far as I have, but at this point it feels like I'm just trying to beat it. I already know how it ends, having knowingly read a spoiler in another comment. I think knowing just keeps me from getting my hopes up.
Also, a note for those wanting to read the crossovers... They were both written after Heroine Shikkaku finished, so yes, they do contain a certain spoiler. Not that it's a surprising one, though.