Yapo's place is truly wonderful! It is full of design elements, it has a gorgeous rooftop terrace, and it is located in a very authentic area of Istanbul just across the street from Pera. Yapo was super responsive and was very flexible with us too. I hope I'll be able to stay here again on my next trip to Istanbul. A true jewel of an apt.
Just two notes of caution: it's on the 6th floor without an elevator and can get a bit warm in the rooms although there is a fan.