If you want to see the whole Istanbul, this is the great place for its location. You can reach the historical center (the blue Mosque and Hagia Sophia) within 15 minutes walk, Taksim 30 minutes walk and the Asian part of the city 40 minutes (20 minutes walk to the ferry and 10 minutes by ferry).
Akif is the superhoster. He explained us how to get his place from the airport, his place was clean and all u need will be in this flat.
This place is my recommendation.