The Duru Suites are in a fantastic location and we would highly recommend staying here to anyone who wants to stay in the Old City of Istanbul. The walk to the Hagia Sophia and the Blue Mosque is only about 10 minutes and the walk to the sea is also about 15 minutes. There is a really nice park within walking distance along the sea as well. There are some pretty amazing restaurants nearby too (Palatium & Dubb). The meals we had close to Duru were some of the best we had in the city during our stay.
Ercan and Yunus were both very communicative and very helpful. If we wanted to have them set anything up for us, they did it promptly and seamlessly. We even had to leave for the airport at 3 a.m. in the morning and they arranged everything. A stay here comes highly recommended from us.