Very central, really nice place. Real value for money. Loved the place, the rooftop terrace and generally how welcoming the hosts were. Would definitely return.
Expect a warm welcoming, and coffee and tea offered each time you go through the 'reception' area. This is more like a mini-hotel, with approx 10 rooms, private sauna, good-ish WiFi, daily cleaning of the room (!!), new towels each day. Loved it.
Also expect some noise - this place is on a steep street, where few cars struggle to go up, and others struggle to park. The windows insulate the noise somewhat, but it's still there.
All in all, I would go there again and I will recommend this place to my friends when they go visit Istanbul.