I really much enjoyed my stay with Umut!
First of all, the location is absolutely perfect! It's a quiet, safe neighborhood. At the same time, you are as close to the metro as it can get in Istanbul. The metro line M2 is the single most important line in Istanbul, and you can reach it in 5 minutes walking. There are two supermarkets and many restaurants and cafes close by. The location is perfect for tourists and also for a long-term stay, as you can reach all places in Istanbul in reasonable time.
Umut himself is a great guy, friendly, helpful and open to chat.
The apartment was very clean when I arrived and Umut always has an eye on cleanliness. The room is big enough for one person and also very comfortable. The living room is large and makes you feel at home. In the kitchen, you've got all cooking equipment you need. The bathroom is definitely ok as well. The best part about the apartment is Bianco, the cat. I will miss both Umut and Bianco and would definitely come back here!