Enjoyed the apartment: very spacious, clean and quite (the windows are facing the backyard), has everything you need for a short stay. The building has an elevator, so you don't have to carry your luggage via the stairs. The apartment is located in a very picturesque part of Sisli, just a few minute walk from the main walking street, numerous cafes and restaurants are right around the corner, as well as fantastic antique shops.
The host was very responsive and helpful, I highly recommend this place.