Riza's place is right in the heart of Istanbul. Galata tower is approx. 5 minutes away and Karaköy port about 10min. The apartment itself is on the 4th floor and pretty spacious, considering the location.. Wifi's great and so is the view! You can see towards the Bosporus bridge on the north side and the hills of Istanbul on the west side.
The only people I would not recommend this apartment are older people, or people with health issues, in particular concerning your legs... As said the apartment is on the 4th floor and the staircase to get there is kind of traumatising...
But other than that I can totally recommend this Airbnb if you need a cheap and central place to stay!