We had a very short stay at Ali's place. The view from the terrace is marvelous, we enjoyed sunsets and had cozy breakfasts there. The flat is cozy, single bed is small but comfy, main bed is a little bit small for me, but still comfortable. You should be careful with a sloped ceiling in the bedroom - it's easy to hit your head. Apartment is very bright, has enough space to chill. There are even some dvd's with great movie collection. Also there was a cooler with drinkable water - very thoughtful of the host.
Ali himself is a perfect host. We had last minute changes in plans, but Ali was very helpful and patient and did everything to make our stay smooth. I would definitely recommend his place to stay in Istanbul.