We had a great stay at Sinem's place. A very beautiful apartment in a great neighborhood (the uphill street should be expected in Istanbul), clean and with lovely decorations. At nights there was no noise and the building overall felt very safe.
There was a little problem with hot water one day which Sinem addressed in the best possible way. We would love to stay there again in the future.
P.S: Just in case you have heavy luggage note that the apartment is on the fourth floor.