Everything was good despite first night when we had to stay at another apartments that are closer to historical area but not that good as the one we rented. Moreover there were issues with cleanliness of the linens. Despite they were after laundry cleaning it seemed that laundry is not good. Saban moved us to another apartment that were better. Next morning we moved to the actual one and Saban took care of our luggage while we were exploring the city.
The apartments location is close to public transport, Grand Bazaar and historical area. At the same time it is in the very "istanbulish" area, with lots of locals and not so many tourists. It is safe as we walked there even late at night.
Overall the place is worth valued. Could recommend to taste the real Istanbul