Perfect place to stay! It's not like a hostel at all! More like hotel or apartment. We've been there for 9 days, and when our flight was delayed Singer 109 gave us another room, although it was really full there! So, it's close to two stations, and it's only 15-20 mins by walk to Alexanderplatz. Also, it's near to clubs!
We really liked beds there, really comfortable.
And you can go downstairs and meet new people, play pool together, go somewhere together.
So, I recommend and will come again for sure!