I stayed two months in a nice room in the 5th floor of the apartment. There were no problems. Basak was very helpful and responded quickly. We had drinkable water, since tap water is not drinkable, we were also provided with detergents for the wash machine. I would recommend the apartment, since it's a good neighborhood, with lots of stairs, when you use the station Yildiz Teknik University (to Levent and Sariyer). However, this area is very close to Beyoglu (10-15 min.), Nisantasi, but also Ortaköy etc.
overall i had a good time, Thanks!