I stayed 5 nights in total with my friend Maria, and two others friends stayed 3 nights. The hostel put us in the same room all together and we didn't have to change the room which was very convenient!
Checkin was very simple, staff very nice available and helpful. You can leave your luggage in a luggage room if you're checkin in early. Breakfast is at 5€ and you have a good range of choice (cereals, bread, marmalade, cheese, cucumber, tomato, fruits, yogurt, tea, coffee, juices...).
The hostel and the room are very clean, it looks brand new and the whole atmosphere is very nice.
It is located 15-20min walking distance from Alexanderplatz or 2 stations from it using U5.
I will definitely come back there and I recommend it without hesitation. :)