Staying at Louisa's was next to perfect! She is a wonderful and responsive host ready to make it as comfortable for you as she can. Louisa and her bf were always there to answer my questions and help me with my plans. We had some great talks together, they are a very interesting young couple.
The appartment is not spacious but it is cosy, and you have all you need at hand. There are a number of cafes and supermarkets around, so you can get a nice coffee in the morning, or buy and cook some food yourself if you like.
The location is great, and you can get to almost any major point of Berlin either by train or by bus from there (including Alexanderplatz, Potsdamer Platz, Brandenburger Tor, Zoologischer Garten, etc.).
I definitely recommend this place to those who travel alone and seek for a good connection with different parts of the city. As a bonus, you get a warm welcome and a nice company!