It's a good hostel option for Seoul even if it's not perfect.
I liked the bed in capsule style, with privacy curtains, that was really good, the bed was comfortable and the private space was spacious enough, I liked the small personal cabinet that you can lock with your own lock. The hostel has a good location, 5-10 minutes from metro station, 10 minutes of the local supermarket (Home plus) and plenty of convenience store around...
Now the negative points are : you need to pay for a towel, the bathroom area is weird and you don't have privacy (the main entrance gives directly on men washroom), only 2 men showers for the whole hostel, often dirty and you cannot put the shower head to get a proper shower (the hold on the wall is only made to keep the shower head right). Toilets were okay.
The whole entrance is weird and norrow, you have to enter some sort of noisy pub to get to the back of the room and go up a narrow and super noisy wood staircase. Thankfully I was on third floor, the second floor looks super noisy because it's close to the pub that have noisy sound until late at night and people go up without paying attention to the noise they make...
The wifi was very slow and unreliable.
It's a weird narrow hostel with no real quiet shared space for work or so, you will only have that small pub which is often noisy and get easily crowded...
So yeah it's a good and cheap hostel option with nice privacy beds, but plenty of problems also...