We stayed at Metin’s place for the month of October. Great experience overall!
By far, the best part of the apartment is the view - it looks just as good in real life as it does in the photos. The neighborhood (Arnavutkoy) is also delightful. It’s a fairly high end residential neighborhood with very good local restaurants, charming cobblestone streets, and walkable views of the Bosporus. There’s an hourly ferry that connects the neighborhood to the main tourist section of Istanbul. Not touristy at all, and thus very underrated among tourists.
In terms of caveats: the apartment itself is clearly not brand new, and has its quirks. Most notably, the power actually went out in the building twice during our monthly-long stay - once for over 12 hours, and another time for an hour. The water heating went out once, which we fixed by restarting the water heater. We also had some WiFi issues during the trip (while the download speeds in the apartment are typically 40 mbps, they were closer to 10 mbps in the month I was there). Fortunately, our host Metin was very responsive during our whole stay about these issues, including helping us set up a separate 5G hotspot for free for me to do my work calls.
Other things to be aware of: the apartment is a 3rd floor walkup (4th floor by US terminology). Location-wise, it’s about a 8-10 minute walk downhill to central Arnavutkoy, but maybe a 10-15 minute walk uphill when you’re going back (it’s quite a hike up!). The ferry is the best public transport in Arnavutkoy, although many buses and taxis also pass through the central area; Uber doesn’t really function in the neighborhood.