Okan and a friend of him were very available for us. As we took 3 different transports to come for Sabiha Gökçen we were not able to give a precise hour of arrival, we just sent them 5 minutes before arrival an SMS ... and they were at the apartment before us! They also explain us how and when visit main sites and when we had a little problem on the toilet flushing they came and repair it in a very short time.
The apartment has a very very good location, every main tourism locations are in a walking distance (between 5 to 15/20 minutes) : Blue Mosque, Aya Sofia, Topkapi palace, Archeologic museum, Grand Bazar, Suleiman Mosque ... If you just stay few days in Istambul, this location allow you to see main locations easily and it's a real pleasure to be able to be between the two Mosque (Blue and Aya Sofia) in 5 minutes just to have a look to them on sunset or on early morning!
The apartment description is exact and if it is quite basic, it is very nice to have a real bathroom with separated shower and not Turkish toilets.

We had a very pleasant stay in Istanbul and hope other traveler will have a so nice experience.
For us, it was first time using AirBnb, I think I will use it again!