The good: location is prime. Situated next to a really lovely restaurant. Breakfast was decent. Beds were comfortable, hot running water available. Good TV. Clean toilet.
Improvements: during my stay I could smell sewage coming from the shower drain in the room. This was fixed by running water through the drain, but I think the plumbing is a bit old. The room was not exactly as advertised, but served us fine. The shower is not in the bathroom which I did not expect. Might be awkward for some people. Some of the hotel staff sometimes came off as if any requests were a chore (even checking in, for example). When we requested our room to be serviced, the sheets were not changed, only noticeable change was that the towels were replaced.
Overall a 3/5 stay. The best thing about this place is the location, as most of central Berlin is within 20 mins walking distance.