I stayed at Pera Neuf for two nights (three days), and I had a pretty bad experience with it. First the positive, the location was very good, in the center of everything and so close to Galata tower and all the restaurants, so you will not be limited in anything in terms of the location. The room was clean and modern, although tiny.
However, on the negative side, there were some issues that made my stay so uncomfortable. (1) First of all, there is no elevator and the room is on the fourth floor. When I mentioned that, the owner became super defensive, saying that it was written on Expedia. (2) What was not on Expedia though was the fact that they do not have working AC. When I complained about it, the owner said someone would come as early as possible next day to fix it. Of course no one came and it was unbearably hot in the tiny apartment. (3) Also, the picture of the balcony does not represent the reality. The view from the balcony was not as nice as shown on the website and was looking towards the back side of the building. (4) the room is not double room, it is a tiny room with one double bed ad a couch, but it is one tiny room.
Overall, I think Pera Neuf has potential but needs to improve its facilities and service. I would not recommend it to anyone who has mobility issues or expects a comfortable stay in summer. Also the Expedia page does not represent the reality of the room!