I don't know a better place to stay in Berlin, and I often stay in hotels with many stars. This is a dedicated Airbnb, with regular cleaning and a fantastic woman at the desk, Mariarosa.
There is no one's stuff lying around in the studio apartment. Instead there's a small perfectly organized kitchenette with a microwave, toaster, dish washer, coffee machine, and all the bowls and implements. The rooms are all different but all face E, which gives great morning light and then cools down during the day. The AC is great. The beds are very comfortable. The bathroom and shower are very easy to use. There is a lot of storage for clothes and a pantry for food. The building is on the corner of a busy street, but with the windows closed and the AC on, I heard nothing at any time of day.
The location is ideal, a short stroll to Bahnhof Zoo, a transport hub, as well as a market and a great health food store.
Do you want to be in Mitte or somewhere else in East Berlin? I don't. Not when I can live near the exciting Savignyplatz and have the S-Bahn every couple of minutes to the museums.
This was always the fancy party of the City, the only one I know that gets better with time, and yet, as Marlene Dietrich sings, Berlin bleibt doch Berlin. Have fun!