Sophia's apartment was great. The bedroom is large, airy and bright with tall ceilings and a large window looking over the apartments across the street (it is on the 4th floor). We didn't see Sophia too much but when we had questions she would try to help.
The area is great - plenty of restaurants/places to eat and a few bars too. The apartment is around 5 minutes walk from the U-bahn, giving great access to the centre of Berlin. If you enjoy running, there is a parkrun, every Saturday morning in Hasenheide Park 10 minutes away.
Only negative is that the shower temperature is a little unpredictable, but it does the job.
I would fully recommend staying with Sophia!