Kristian and Peggy's home was perfect for our 7 week long stay in Mitte. The location is spot on, with many great cafes (our locals were St. Oberholz and The Barn for great coffee, you can also work from both cafes using the free wifi), restaurants (our fav was Organic super foods and liquids) and grocery stores (include - Bio stores, REWE, Lidl and more, all within walking distance!). It's close to all the transportation lines, but you can walk to all the main attractions if you want to stretch your legs or ride a bike. We cooked at home everyday and found the kitchen well equipped for making lots of delicious food.
The bathroom is very small however. But all the other pluses rule out this minus. I hope you enjoy your stay as much as we did!