I'm enjoying it a lot, but I can see people having a problem with the inconsistent pacing that can be quite a slog, Han Suji's development is taking way too long and she was actually a better protagonist when she was heavier, and aside from her transformation into being hot it doesn't feel like that much has actually happened and the story is only now starting, even though the series is almost halfway over. Also despite all this time we only get a glimpse of what these characters are really like, besides Han Suji and Lucifer.
I'm not saying that to shit on this series, I like it and if I wrote a paragraph about what I like about it it'd probably be a bigger paragraph than the negatives, but I do see why there are enough people to bring it down to a 6.87. The series has potential, but not everyone's willing to wait for that potential to be met.