Umit is a fantastic host and his apartment really is a beautiful place. He responded quickly and there were no major issues. The neighborhood is nice and quiet and is a short 25-minute walk to the center of Kadikoy and a 35-minute walk to the ferry. There are plenty of small grocery stores nearby and plenty of restaurants. Umit was kind enough to leave us some food in the fridge and cleaning supplies for laundry and keeping the apartment clean. The back porch has lots of plants and is a great place to have a coffee or drink and chat.
We stayed for 49 days and greatly enjoyed our experience. However, the wifi often did not work and would generally only work in the living room near the router. This was partially addressed by the end of our stay but was still not fully resolved. If he is able to upgrade the wifi, this will be essentially a perfect place. This, however, was a small complaint about an otherwise good experience.
I would recommend staying with Umit and would gladly stay again.