It's a good/nice space. Great location, friendly and helpful staff, and the apartment is very nice. The building's great location and proximity to things also means that you will be woken up at 5am for the call to prayer, so be mindful of that.
What stood out for me was the flexibility with Cihan. Upon arrival, I wasn't pleased with the noise the apartment got on the first floor. So I was taken to the 4th floor apartment instead where I stayed. Cihan also allowed me to have an extremely late check out time as well with no issues which was much appreciated. Overall I'd recommend staying here and would stay here again the next time I'm in Istanbul. It really was pleasurable apartment to stay in.