If you are group of few people I can highly recommend the apartment of Marco and Deniz. The view is just stunning, we spent a lot of evenings enjoying it. Plus it is located in a very nice area - a lot of nice cafes and restaurants around, but very quiet area at the same time. Taksim square is only 10 minutes walking. Karaköy district is also around 10 minutes walking. We will definitely come back.