This apartment is one of the true treasures in Istanbul. Huge space, lots of light, perfectly decorated, comfortable bed + couch... everything was perfect. And the Sunday market is just about the most local experience you can have. When I come to Istanbul, this is the only place I will stay at. It's perfect.
Per the comments on the neighborhood, this is the real Istanbul! None of the touristy fake stuff you'll get up on Istiklal. Families live here, chat here, hang up their colorful laundry together, so you truly do get an actual feel of the city.
Book this place immediately, and for longer than you think.