We stayed for 1 night. The guesthouse was a bit tricky to find, but a nice man saw we looked lost and showed us the way. The room was clean and comfortable enough for the 1 night. It was quite hot and humid, and there was not a way to turn on the A/C as it was early March, so they would not give us the A/C remote. We ended up opening the windows and that seemed to work fine. The location was convenient as it's just across from Seoul Station.
In term of access to station is perfect but the place is somewhat not good for air cleanliness in my perspectives.
I would rate 3 out of 5 because of that .