I didn't get the chance to meet Barbaros but Ali was at the apartment to welcome us. He was extremely helpful throughout out stay, offering assistance 24 hours a day. The apartment was perfect, very well located walking distance to all the major attractions. There are many shops and supermarkets in the neighborhood so it is very convenient for all your shopping needs.
The kitchen is very well equipped and the rooms are beautifully decorated. Ali also arranged airport pick up and drop off without any issues.
All in all, a great place to stay in Istambul.