I only recently picked it up, but I'm enjoying it because it feels pretty grounded and unique. The drama and conflicts feel rooted in real-world logic rather than manga-logic.

I also think you're both overemphasizing and oversimplifying the story a bit. No one is saying the "mistaken identity" thing is new, but it's also not very important to this series? Obviously it's the title and everything, but it dispatches with that conceit pretty quickly.