Katharina is a really friendly host and made me feel very welcome. Communication prior to arriving was straight forward and easy.
I really enjoyed staying at Katharina's place while in Berlin for research. A super light and neat appartment in a great area and although right around the corner from great restaurants and places to go out, the flat itself is quiet and was ideal for me to come home to in the evenings. All you need is within short walking distance and public transport to get around in Berlin is around the corner as well.
All in all: a great experience and I can of course recommend staying at Katharina's.