The rooms are nice, clean and it's a good location. Unfortunately the staff locked my room with the master key while I was out. When I returned at 9:30pm after the reception was closed, I couldn't get in. There are no staff around whatsoever after 9pm, not even an emergency phone number.
This meant I had no way of getting back in and was stranded without my belongings and with nowhere to sleep.
When my roommate returned and was locked out too, we had to book a room at Schrott next door and sleep there instead.
Fortunately when we returned the next morning when reception reopened, they were able to let us in and our belongings were still there. Apparently this also happened to another room the same night. Fortunately I received a refund without too much fuss.
To the management: please get an emergency phone number that is available to resolve issues like this overnight! This is the first place I've been where nobody is available to help whatsoever overnight.