Started reading on a whim because I heard it was messed up and, sure, the piercing chapter did a number on me (I kept cringing and saying "oh no" over and over and it was the chapter it took me the longest to finish), but I ended up reading the whole thing because I think it does a great work of balancing the awfulness of the characters.
I don't think Airi is worse than Hina, or viceversa, Hina has stated she could have walked away from Airi's abuse if she wanted to but she chose not to and I actually cheered on when Hina became the abuser in the situation because it was the culmination of all those earlier clues that she was as bad as Airi in their relationship.
Speaking of which, all I hope for an ending is that they end up together in their codependency and their enabling behavior (I'd also like a comeback from bully Airi, but I don't think we'll get it). Ah, and for glasses girl to end up exposed because hers is a suffering I could probably enjoy.