Having stayed in different areas of Istanbul, I would highly recommend Firat’s place and Kadiköy in general. Apartment is clean and spacious with lots of light and great views. Very comfortable especially if you are here longer or plan on doing some remote work. Easy access to the ferry or metro which takes you to the historic center in half an hour. Kadiköy is a great neighborhood, and there’s no shortage of cool bars and restaurants within walking distance of the apartment.