We reserved the 4ppl room but there were only three of us, the room offered two twin bed and a double so the space was quite big for us ,even open up all the luggage.
And the position is 5 mins from station but at the opposite way to Main Street of hongdae,so it was quiet at night.
The only thing that may be bothering is that the soundproofing. You may easily hear the noise next room.
Overall the trip staying in house 740 was a great experience.