My boyfriend and I stayed here for 3 nights in April/May. The hotel is very easy to find from the Ernst Reuter Platz underground/bus stop. Check in was easy and the gentleman was very helpful with maps etc.
The room (standard) was on the small size, but more than adequate for us two. Very funky and modern. The bathroom had an excellent shower, a proper power shower not one of them awful rainfall showers a lot of hotels are going for these days.
Only had a couple of issues which leads to only 4/5 - the towels are ridiculously small, the room was almost unbearably hot even with the window open (no AC) and the TV only had 2 English channels, which I know should be an issue as we did spend most of our time sightseeing, and we were in Germany, but it still bugged us, especially as the wifi wasn't fast enough for Netflix.
Overall, it was a nice hotel and we would stay again if we were ever in Berlin, but maybe in winter!