I watched the series and the movie side-by-side, and here's what I've found: in the series, there are several scenes that are cut out off the movie version, and which I think contribute to understanding the characters and the plot a bit better.

What I liked:
* All of the characters in the boarding house. They each have their own personality, which we can see even though the story's so short.
* The acting. All of the actors make it possible for us to get to know the characters and their thoughts.
* I liked the friend from college, Bong Deok, the most, who showed remarkable depth of character. Kudos to his actor, I'd like to see him in more dramas.

What I did not like:
* I think they people responsible for the project chose the wrong story for their format. For these short dramas / average length movies you cannot have an ensemble drama and expect a cohesive storytelling that has enough depth to be satisfying. Something will have to be left out, and it shows. I imagine the original work this is based on is much longer and allows for more character development.
* Why did they bleep out the swear words, even put a flower over the actor's mouths? I don't understand why they did not just put a different text for the actors to speak there, if they wanted to keep their low age rating.

Overall impression:
I do not regret watching this show, as the story was cute, the characters likeable and the actors did well. But this is by no means a must-watch; we have enough BL dramas by now that we can choose those of higher quality.
If you have not yet seen it, but want to, I recommend watching the series, not the movie. Although the change between episodes is a bit annoying due to their shortness, the scenes which are not in the movie are entertaining. Also, the movie's background music is sometimes a bit too strong.