I'll just write the pros and cons here in a list form.
This drama is actually a slice of life drama. It's just like an anthology of short stories but the roles are the same.

Pros (not in any order):
I. OST-rich
2. No boring episode. Here, you have 5 main roles to watch, they are funny and are true friends.
3. This drama grants you a LOT of comedy in each episode
4. THE MOST REALISTIC KDrama I've ever found
5. This drama DOES have romance stories with perfect ratio (the drama isn't overshadowed by romance scenes).
6. This drama does NOT rely too much on past stories/conflicts. The past is just to explain that those 5 characters are friends since long ago and the history of how they became friends.
7. Rich of BEAUTIFUL LIFE STORY, no unnecessary plot twist.
8. WILL make you understand some of the medical terms and procedures.
9. THE BEST NATURAL COMEDY in K-drama ever. You will laugh just by watching their acts, in fakin' EVERY episode!
10. You will also be teary because of the kindness or sadness in the story. This drama's setting is in the live-or-die building after all.
11. It's planned to have the SECOND SEASON!!!

Cons:
1. It's too short. Only 12 episodes (1 hour ++) each. But, still not enough for me :(