We had a great stay at Handan's flat. The main thing that made it such a great choice for our stay was Handan - we didn't get to meet her in person but she was incredibly helpful with recommendations for places to eat and drink (all of them good), and really flexible with check-out.
The flat itself was simple but nice, and a good size for three of us (two bedrooms and one sofa bed in the living room). It just has one bathroom so probably better for a family than multiple couples. A small issue is that the street it was on was really noisy during the night, but the trade-off was a brilliant location in walking distance of the bars and restaurants on Tomtom, Nevizade and across Karakoy, so I'd recommend it for anybody wanting to be out and exploring the city a lot.