tl;dr
if you are planning two days of partying and need a place to crash.. if you do not need a fully equipped kitchen and prefer being drunk than reading a book this might be your place.
You will find slightly better places for a little more money, e.g. the EastSeven Berlin Hostel or Odyssee Globetrotter Hostel!


Location:
Really well located close to the U1 "Görlitzer Bahnhof". There are so many nice restaurants, bars and cafes just around the corner.

Staff:
The "staff quality" varies heavily. In the evenings they tend to get drunk. Also sometimes I had to wait 5-10 minutes in front of the door waiting for someone to open it.

Security:
The lockers are really really baaad.. and the staff recommends putting your valuable stuff into their private locker room. This was a real hassle when you'd like to access your notebook 2-3 times per day. They really should buy new lockers!

Perfect place, location is excellent, just few steps from metro, and just next to main street where are pubs and restorants.
Staff is great, very helpful!!
Pool table, bar that works late: perfect! Great place to meet a lot of young people, have fun, chill out!
Wifi is a little problem: you have to take new password every little a while, but not such a big deal.
If you wanna have fun in Berlin: it's a perfect place!!!!!!!

The atmosphere was cosy and nice.
The dorms were big and very noisy so it was hard to get some sleep.
The showers were not very confortable but kind of clean.
The hostel is well-located, near clubs and bars and not far for the center.

Excellent location, very nice rooms and good restaurants nearby.
I have recommended this hostel to all my friends going to Berlin.
The staff was amazing! The subway is in front, and it is very easy to reach coming from the central station.