I read this in about a week. Had to. It keeps you peeled to its pages.
Charaters are relatable, almost always feel real.
While there are misunderstandings here and there, nothing major, so don't expect the usual "she comes at the wrong time and he doesn't have the time to explain himself and there you have the start of drama".
The plot was fairly interesting, the story keeps a brisk pace, but not too fast either. Things seem to happen naturally, maybe beside that one time a certain stepsister decides to break up while being still in love and having absolutely no reason to (or, bad reasons maybe). But hey, it's people, they make mistakes, expecially when feelings and emotions are involved! We're not rational machines that always output the best possible response to each scenario.
The style (both writing and drawing) were a little above meh at the beginning and kept increasing in quality. The mangaka showed some (or maybe, LOT) fanservice, which surprisingly didn't really ruin the whole thing. I still struggle to understand if it's an hentai with story, or a story with hentai in it... Just joking.
The author wrote a masterpiece, and while the ending wasn't what I expected, I feel it made sense.
Don't read it if you're emotionally fragile right now. Settle up, be sure you and your partner, if you have one, are doing great, have no problems in real life. Then you can enjoy the drama and not cry too much.
Just to add to how good this thing is, I came and registered to post this rating. And I've seen other masterpieces like Death Note, Assassination Classroom, Code Geass, and more emotionally engaging stuff. Still, this strikes a chord in my heart.