This is without question the best Airbnb I have ever stayed in. The apartment is very large. The main bedroom suite is air conditioned and has a sink and tub. The second bedroom/office was more than big enough for my friend who I traveled with.
The location is also perfect, located near Galata tower on a quiet street with some excellent cafes. And the apartment is just up the hill from one of the main ferry terminals (~15 minutes walk downhill to Karakoy terminal; note: Istanbul is a very hilly city).
Zehra was also very helpful and communicative. She coordinated a taxi for our early morning departure and even spoke to the taxi driver on the phone to make sure he didn't rip us off.