Gufran's flat is perfectly located in quiet part of Kadikoy, possibly the best neighbourhood to stay in if you wanna see the real Istanbul. Meanwhile everything is near — waterfront, supermarket, small shops, pharmacy, food market, transportation. Pizza Moda 20 meters near is wow.
The flat is on the first floor (that might be important for some people taking into account Istanbul stairs style), it is nice, has its own spirit, well-decorated and has everything you need. Gufran is amazing person, very helpful and easy in communication.
I do recommend staying here if you want to join real local life and discover the city from inside.