My family of 6 adults stayed comfortably at Julia & Tarkan's lovely apartment in the Galata area from 26-31 Dec '17.
The apartment is very conveniently located. We can literally walk to all the main tourist sites and there are nice restaurants, cafes and a supermarket all within a few minutes' walk from the apartment. The main shopping streets also very nearby.
Our special thanks goes to the wonderful apartment manager, Tauskin, who was very helpful and extremely responsive to all our requests.
The only down side was that the wifi was very unstable despite the fact that Tauskin personally came to reset it twice.
Also the next door neighbor was doing major renovation which created a lot of dust.
Overall we had a wonderful stay and we would highly recommend the apartment. We ourselves will definitely use the apartment again should we revisit Istanbul.