So I stayed in this room now for more than a month (and I have already booked it longer and will stay an other month and a half) during my stay in Istanbul. I am here for studies so I was looking for a place that could really accomodate me for long term and this place fits the prupose. I have a good bed, storage space, a chair and a desk. First of Merve and Arif are really nice hosts, they met up with me on my arrival and showed me the way. The room and house is really clean and Merve and Arif are always ready to help of there is any problem. All facilities are present and we are all welcome to use them, which is ofcourse convient when you live here for a longer time. In the kitchen there is no real table to sit at which is a little inconvient but because some of my classmates are living in the appartement across the street (also theirs) we always eat there. The bathroom is a little unusual as the shower is not a sepeater box, but it works perfectly fine with warm water and good water pressure. The neigborhood is full of families, so during the day it's perfectly fine to walk around. I myself was not so comfortable walking home alone during the late evning/night but like I mentioned I was not here alone, so it was not such a big problem (and it also depends on people). Otherwise the location is very good, a 5 min walk from Istiklal, which is the main shopping street and not too far from a metro stop (Sishane). There is also some grocery shops close by and if you are here to study, Bilgi University is only 3 min away ;-).
I would definitely recommend this place for long or short term stay. If you are not sure, Merve is also really helpfull (and super fast) in answer questions about possible stay.