Selim is a very nice and helpful person. Before our journey he helped us a lot. He arranged a Taxi for us from the airport to the apartment (highly recommended).
The apartment is quite nice. Very beautiful place with comfortable beds and basic kitchen stuff to live. The location is amazing. With couple of meanings walk, you will get to the heart of touristic areas such as Hagha Sofia. The neighborhood is full of restaurants and grocery shops.
However, there were some problems/points that were a bit annoying:
1. there is a small water container (I'm not sure about its name) which can be seen in the photo from the bathroom in the first floor (hot tub). This container was full of really really dirty water when we arrived. When I was evacuating it, there were even some big pieces of dirt in that which was so hard to look at. Moreover in the upstair bathtub, the water couldn't go through fast, so I had to wait after every shower and this took around 10 min.
2. Something that we really needed was an iron (and it was listed in the apartment properties) and although I asked for it several times, my request was ignore by Selim. Later he told me that he had a problem and I could totally understand him.
3. The floor was not very clean. On the arrival day, I cleaned part of the bathroom floor in the first floor and the tissue was dirty after that.
Again I would like to thanks Selim and hope these info become useful for all the travelers to Istanbul. All and all it's very close to be a perfect place for your staying but it need a bit of more effort.