There are many, many, many things to love about this hostel. It is perfectly located to see Berlin's sites, convenient to U2 line, walking distance to AlexanderPlatz, lots of shops, restaurants, and grocery stores. The place is spotless, really nice bathroom facilities, and comfortable beds. The lounge area has a cozy fireplace, pool table and lots of seating. Breakfast with fruits, yogurt, meats and cheeses. All of the staff were friendly, knowledgeable and helpful. Even as a 60+ year guest, I felt welcome. The other aspect of the entire Pfefferwerk compound was that it includes social programming to help folks to train for jobs.
I stayed in both a double room and then switched to a single room. If you are going to stay in the single room, ask about where it is in the hostel. I stayed in Rm 08 which is the only guest room in a small corridor with the luggage storage closet and staff office. It was a spacious room, specifically designed for someone with physical disability; but its location was loud and felt odd. The double room on the 3rd floor was really nice (although I could have used a light over the mirror in the room). The beds are two separate twin mattresses on a double platform. Fine if the person you are sharing with is someone you know well, a bit odd if you end up having to share with a stranger. Upper bunks in the dorm rooms are really high. Only real negative for me was the wifi signal - worked fine w/ phone but couldn't get laptop to connect