So I decided to watch this because I'm a kpop fan and I was willing to watch it since they released the last episode. Now I expected more of it, but it's not like I hated so here goes my opinion divided in parts.

Story
It starts really well and it's so interesting, but as we advance in episodes, it starts getting a little bit boring. However, I was quite satisfied with the ending, even if it didn't get the romantic one I expected. I like how the members of the group are really different from each other. However, they didn't say anything, and when I say anything is anything, about Woo Yeon, and he's one of my favorite characters. Gotta say I loved Yoo Chan, such a lively character with a deep story.
If you are looking for a romantic drama, this isn't it, even if it looks like it. I think it needs to be said, because I missed more romantic scenes and to be deeper in that sense, but it's more centered in the stories of the members (apart from Woo Yeon, because again, and I'm really angry, he doesn't have one) and the relation between them.

Acting / Cast
They did act ok, but in some times I felt like it was a little bit exaggerated. The cast was brilliant, I loved all of them and how they represented their characters.

Music
Please help me stop listening to Beautiful Breakup because I think I have a problem. I have been watching this kdrama for more or less two weeks and I can't stop listening to it, when it appears in one of the first episodes, or in the first one, I can't remember exactly. Anyhow, the music is amazingly good, all of the songs, ALL OF THEM are on my playlist already.

So overall it was enjoyable, but as there was almost no romance it was meh. I mean, if the drama didn't have any romance to start with, it would have been a lot better, because the evolution and relationship between the members made it really good, and the ending was so good too.
Note: I love the CEO, everyone needs a CEO like him in their lives