The apartment is small and cozy, it had all the necessities for a longer stay while remaining affordable (I'm a student).
It is very well located in the center of Kadiköy, in a quiet street, next to the bus, metro, and ferry stations. This made it very easy to go for walks in the neighborhood or along the sea, going for shopping or to restaurants, and as a starting point to visit other parts of Istanbul.
Aysegül is a nice easy-going person who was flexible and fast in replying, I had good communication with her.
I had a wonderful time in Kadiköy!