My sister and I had a great stay here, and we stayed for 4 nights. The staff was helpful and friendly whenever we needed them, and the room was nice and clean.
The hotel is situated in an absolutely lovely neighbourhood, and within walking distance to many of Berlin's attractions, including the TV tower and the Berlin Concert House. However, the closest grocery store was far away from the hotel, which was weird since everything else was so close.
And the facilities (fitness room and spa) were both dissapointing. The gym was very small, only had a few different machines and no extra room for stretching/yoga etc. The spa included a few chairs and a sauna.
Despite the lackluster facilities, I highly recommend this hotel!