We stayed for 1 week, and we're happy with the place and our host Taygun. The apartment was perfectly clean, cozy, and had a very nice view, especially at night and at sunrise. We used it's compact kitchen few times.
Taygun was very responsive, and helped with everything we need.
The neighborhood was nice, had some nice small shops and cafes around. Galata Tower and Sultanahmed is walking distance away. In case of need, we used tram line, which is just below the flat. The ferry to Prince Island is very near as well.
Thank you Taygun, see you next time in Istanbul!