We had a very good time in Istanbul.
First Nida's place was perfect: the appartment was really nice, bigger than we thought for 2 people and very clean. Then the area is nice, closed to Taksim where there were a lot of things to do. Our best place was the 360: a rooftop which is a restaurant and a club on Fridays and Saturdays. Karakoy is also closed by walk. Near from the Hammam of Karakoy there were also very good restaurant. Some more typical, other more trendy.
Globally Istanbul was a very good city to enjoy food, see very nice historical places, do shopping. People are very nice. People who were in charge of us were very friendly. Hope to come here soon in Nida's appartment.