I had a very nice stay at Sertac's place. The whole building consisted of studio apartments, and I assume that they are all equally clean and well taken care of.
The room I stayed in was great: it looked just the way it was shown in the pictures, and it had everything needed for a short stay.
The bathroom had a very good, spacious and clean shower, there very plenty of towels and a hairdryer. I didn't get to use the washing machine, but it looked new and functional. Soap, shower gel, shampoo and toilet paper were also all there.
The kitchen was quite nice too: there was a small electric hob, which was a bit old, so took a while to get hot; a pot and a pan and plenty of cultery and plates (more than enough for one/two people).
The room itself is quite big for one person, the bed was comfortable and new, and what I particularly liked was the fact that there were plenty of sockets. The curtains were thick and blocked the sunlight well. I didn't have a chance to use the AC, but it was nice to see that it was there. The wi-fi connection was stable, although I'm not sure whether the speed would be high enough to work from the apartment.
I stayed in one of the rooms on the third floor, and I was lucky as my windows looked overlooked a quiet street. The building had an elevator, which, as far as I know, is quite rare in this area. It was very close to Taksim metro stop, and the Cihangir area is very pretty and tourist-friendly: there are lots of shops and cafes around.
Sertac was a great host - it was easy to communicate with him and he was very efficient and fast arranging things. I would definitely recommend staying at his place, and would stay there again myself.