Do not watch this drama, if you expect it to be about music. Frankly, you could change "EXO" into any other "celebrity" without any change to the script, except for replacing the name. Even changing it to someone not famous, it would not be too much of a difference. The "celebrity"-storyline is not exploided.

I only wanted a drama about music (or music with a bit of drama), did not even know what/who EXO was before reading another review and even then thought for half the drama, it is a four-member-band. But I definetly did not become a fan due to this show. There was maybe half of a snipplet of a concert, I guess, so becoming a fan of what?
This really made it difficult for me to rate the music. KPop (or better called KRap) may or may not be your music style, but it was not part of the show and the soundtrack was just decent background music. So no rating of EXO's official music (which I will not rate here).

Also two things to know before watching:
a) Episodes are only 15 Minutes, so expect rather a filling than a show itself.
b) the actors are musicians and dancers, not actors. They are ok, but not extraordinary. I somehow pity them, since they were probably forced to play a part in such a show.

The story is just a story, nothing much (literally, since it is less than 4h in total). A bit stupid in the beginning, a bit more serious later on, but more something to fill the time, since the story is very clearly about reaching out to already existing hardcore fans. Since I am not one of them, I was not an expected audience in the first place.