My friend and I had already been staying at Davut's place, though we booked his other room previously. We continued our stay in this room for 6 more nights. It was a wonderfully comfortable and hospitable experience. Davut's house has all the amenities, as advertised: a great kitchen, washing machine, highly functional internet, and lots of space and light. It's also remarkably quiet for any area, but especially impressive because it's right in the heart of Kadikoy, allowing easy access to shopping, coffee shops, bars, grocery stores, and the nearby beach.
Davut himself is an ideal host: he's clearly a kind and wonderful person, and is a delight to be around. I would definitely recommend staying at Davut's place!