Furkan Mustafa is a great host who is almost always can be reached by AirBnB messenger or phone, also he wrote a really detailed instruction how to find the flat in a labyrinth of street near 4. (Dördüncü) Levent metro station.
Place itself is small, but has all enough even for a long stay (well-equipped kitchen, comfy bed, washing machine) and is 7...10 minutes on foot from the nearest metro station, also you can go from there to Sabiha Gökçen (SAW) airport by bus in 1 hour.