Before our arrival we got a description how to get to the apartment, even if it was difficult to find. So better check the exact address before you go there.
The apartment was ok, it isn't a typical AirBnB apartment, it is more a hotel room. So we weren't able to cook, the equipment is quite easy. Smoking seemed to be allowed in the room. In addition there is a cleaning service every day.
The apartment was very very loud. Even with closed windows the street was very noisy by night.
The location is good. It's next to Taksim Square from where you get easy and quick to the different parts of Istanbul.
If you are looking for a simple stay for a few days it is ok. We spent the whole time discovering the city so it wasn't that necessary to have a luxury apartment.
The contact with Suphi was well working.