The apartment of Rose and Mustafa is just fantastic! Beautiful, spacious, well-equipped. There were six of us, and the apartment suited us very well with its three separate bedrooms. We also liked spending time in the big hall, it was especially nice to be there during morning hours with sun coming through the windows. One thing to mention is the internet connection - it is really slow. Though we know that it is not that uncommon for Turkey. Apart from that, we liked everything. And let it be one more reason for guests to spend more time outside :)
The location is also a big plus: a street that is quiet for Istanbul, Galata tower and Karaköy district are just 5 minutes walk, and also there is a tram stop some 2 minutes away where you can get a tram to reach such sights as Hagia Sophia and Grand Bazaar.
Finally, our hosts were really friendly, attentive, and understanding. And they quickly responded to all our messages. We highly recommend this apartment.