What a great location and such friendly staff! It is absolutely like being in someone's house, which may be intimidating to some people. Super clean bathrooms and rooms, and attracted a good group of people. I would totally recommend this place.
The location of the hostel is great (right in the heart of the Plaza de la Merced). The staff are pretty friendly, speak good English and Spanish, and the atmosphere is very much of a party hostel (and they advertise this in all of their information). My "single" room was basically a double bunk bed in a closet, but my things were always safe. Realize that the party hostel vibe brings in some "interesting" personalities with different ideas of cleanliness ;) WiFi didn´t work often.
Location was a little away from the city centre (about a 7 minute walk). The local coffee shops are pretty good and less touristy. Staff was nice, although I rarely saw them around. I saw the cleaning staff in the bathrooms, but the ceiling was crusted with mold and I had quite a few allergic reactions in the bathroom. The room was simple, like a college dorm room. Interesting clients. My last night was plagued by a woman who left her keys in the room who rang the doorbell for 30 minutes at 4AM.