HIGHLY RECCOMEND!
My mother and I visited Berlin for a 4 day stay, and we had a fantastic time despite the unlucky weather. Maddalena's flat is just as the pictures show - very spacious/bright and very clean.
Here are my top points:
1. Location - The street that the flat is on seemed to have just about every recommendation of bars, cafes and restaurants that we found on guides online. Really - this whole stretch of street is perfect for interesting and non-touristy bars and cafes etc., we couldn't believe they could all be in one place. And of course, it has great public transport links (but everything is walking distance anyway).
2. The space - Just as the pictures show, the living room is huge and bright due to being high up and having tall windows. Great bathroom and kitchen facilities. Also, the apartment itself is very safe in terms of access.
3. The host - Maddalena was great with communication and extremely friendly and welcoming. My mother left her work Blackberry plugged into the wall when we left for London, and Maddalena offered to help it return it to us with no complaint - including the tedious effort of bringing it across town to my mother's office in Berlin to post it back. We really appreciated that extra effort.
Thanks Maddalena!