We had a really good time, the neighbourhood is full of nice Cafés and Restaurants. Also the metro / Marmaray / Ferry stations are close to the apartment. The apartment is quiet and has a cool ambience. Everything you need is there, all equipment is working fine. WIFI is fast, you can also watch Netflix on the TV.
The only downside was, that we didn´t use the garden & terrace that much, as many cats are "hanging out" there. By the way, during your stay, you have to feed these cats. Kadiköy is famous for the "cat life" ;)
Onder was a really kind and helpful host. The communication was always good and flexible.