I started watching for two reasons: the presence of Choi Siwon as one of the protagonists (I never saw him in a drama before) and a short clip of John Jang and Park Ji Wan (Park Yeon Woo and Son Hwa Ryung) from the show. I also liked the premise enough, but unfortunately things didn't go as smoothly as I hoped.

This show has two main weaknesses: it tried to use certain tropes and elements of the story way too much, to the point that it got very boring, and at the same time it introduced multiple interesting themes that could have been explored more but ended up being set aside.
The love story between Yeo Reum and Jae Hoon could have ended in the span of the first few episodes (after a few fixes here and there), but instead the writers tried to drag it for longer, which made the series oddly tiring for me to watch. Any kind of obstacle that comes between the two main characters doesn't feel threatening to their love in the slightest (not Han Ji Yeon, not Kang Chae Ri, nothing at all), so it ended up feeling as entertaining as watching paint dry. I was half-hoping that this long wait could be useful for the two of them to actually mature, but that wasn't the case either.
The show actually introduces multiple themes that could have been explored better: not only the environment behind the production of a reality TV show, but also eating disorders, mental illnesses, past traumas, relationships with family and colleagues, and so on. All of these themes ended up being neglected in favor of the boring main plotline, so I couldn't help feeling robbed in the end.

Like many others both in the comments and in other reviews, the only reason why I didn't regret watching this drama and why I'm giving it such a high score is the unexpected couple of John Jang and Park Ji Wan. John Jang went through a beautiful character development, and Ji Wan's character also got to show multiple sides of her character. That, combined with the lovely plot they got, turned them into the most interesting part of the entire drama. I wouldn't mind watching the series one more time just for their moments.

Overall, I have mixed feelings about this drama. It was entertaining and I was able to finish it, but I didn't enjoy myself all that much. I only recommend watching in case you don't have anything else to watch at the moment.