We had a lovely time at this place! The location of the flat is perfect: you are at 2 minutes from the heart of Galata, but at the same not directly in the main streets.
From the airport, you can take a cab and reach it within 30-40 minutes. It's easy to find and to enter.
The flat was in accordance with the pictures. The only remarks we would have is that the shower sometimes spontaneously switches to cold water and the bed room faces a courtyard, so you might hear the noise if someone is talking outside or playing music.
The hosts were very helpful and quick to answer.
Finally, we would recommend this place if you are wishing to travel to Istanbul!