I read all of the other reviews before I stayed here, and so I'm not surprised a bit that my stay at Mittendrin was fantastic. Sabine is delightful and dedicated. She makes every effort to make you comfortable and tend to your needs. I booked the smallest room, but since she had someone else wanting that room for a longer stay, she bumped me up to a nicer room at no cost. She gives free coffee and water, which few hotels do, and she will even do a load of laundry for you for 10 euros, which I desperately needed after already being a week and a half in Germany. Sabine also gives good tourist advice. Her shopping recommendations are for more high end places, but since she is a Berliner, she also has good advice for food and shopping at more moderate prices. Also, though she says her English is not great compared to her German, I had no problem at all talking with her.
Aside from Sabine being the sole host (and a fantastically kind and social one), Mittendrin is unique in that you're staying in a Berlin flat rather than a proper hotel. This means that you will occupy one of only four rooms, you will share a bathroom, and you will share a breakfast table with other occupants. It also means that you get a hint at what living in Berlin is like. I came in quite late a few nights, and the creaky wooden floors made me fear that I'd wake my neighbors, but other than this, I had no stress while staying at Mittendrin. This hotel is close to food, shopping, and transportation.