I have been traveling in Turkey for over two months and this is definitely one of the best places to stay in Istanbul. The location is great, very central but the noise on the street doesn't bother me.
The apartment is large and spacious with glass windows, which can make it a little cold but there are heaters in every room so it was not a problem.
Downstairs is a nice cafe with delicious and inexpensive food, which was also very convenient. The owner is kind and helpful. I highly recommend this place to stay.