In my experience Kumkapi is not the best neighborhood in Istanbul--old, noisy and in general not a regular tourist oriented area. So you need to adjust your expectations if you are going to stay in this part of the town. The listing is an old building with 3 units, but fairly clean an organized. It is about 20 minutes walk to Hagia Sofia and Grand Bazar. Our unit was on the 3rd floor, which means taking lots of steep spiral stairs. The owner is professional, speaks English, fast at communication and offered us a ride from Attaturk Airport for an extra fee of 20 Euros, which is really helpful. Overall the place is ok for its value.