We stayed at Marlene's place for about 500 nights! It was not just a trip but a long happy period of life.
Marlene is a great host, always ready to help and easy to communicate. The house is a beautiful Berlin's altbau located in the best and prettiest street, walkable from all the key places both in Prenzlauer Berg and Mitte. There are many good restaurants and yoga / pilates studios in the area. There is a nice sauna and swimming pool just around the corner at Oderberger's. The apartment itself has everything for a long and comfortable stay (maybe an addition wardrobe would nevertheless be a good idea).
In general, it was one of our best stays ever and in Berlin particularly. Totally recommended.