We are a family of 4 from Germany with 2 girls ages both 7. Convenient location, just as described. Minutes from both harbor and wonderful fish restaurant area (Besiktas CARSI).
We liked staying at Esma´s apartment very much. As Esma is not living in Istanbul the provided contact Ozan was hosting us. He is real estate agent and his office just next to the apartment. Both contacts, Esma and Ozan, were very friendly and helpful (via mail,phone and sms).
The apartment itself is clean, quiet at night and save.
Also a lot of nice cafes nearby to get breakfast or dinner before going to the city center (normal prices).

Bus-Station : only 5-10 minutes walking distance
Besiktas Harbour : 5-10 walking distance (great Hop-on Hop-Off Golden Tour Boat Trip; great for kids e.g. Pierre Lotti and Miniaturk)

Many thanks again Esma
Ahmet