I stayed for a week at Erhan's place. I was greeted and communicated mostly with Riza, Erhan's brother. The communication and responsiveness were great. I first arrived later than we agreed because of the flight delays, but Riza was kind enough to walk me to the apartment and show me around. He also helped me out with some side issues during my check-out day. I really appreciated their support and assistance.
The apartment is right next to Istiklal street and bars, so some noise was present but it wasn't too bad for me personally. 5 mins walk to the metro station. Walkable distance to the Galata tower, Museum of Innocence, and Taksim square.