We stayed in this apartment for a month. It had minimalistic and comfortable furniture (comfy and clean couch and beds), good wifi, nice work table in a master bedroom (which was bigger than in the photos), heating system was very good for the end of rainy November. The building was safe with quiet neighbors and a very friendly janitor. You could watch cute Istanbul cats outside of the window.
Mustafa had good and professional communication, they fixed everything that we asked about and provided late check-out for an evening flight. Thank you very much!
Unfortunately, we didn’t like the location. The apartment was located on the second floor but the windows were actually on the "ground" floor, with a view of a street with big stairs (Istanbul is a hill city), where there were constant passers-by in the window. This also makes the apartment very dark. Expect to have lights on most of the day.
Also, the smallest bedroom window has a view of a courtyard, which is more like a sump of the building. It looked very creepy and smelled like old greasy oil from the buffee from the (actual) ground floor, so it was hard to keep windows open. The apartment was in the noisy area because of an active road traffic, as well as people crossing the street to a big school and noisy people in the building across the street. If you would like to go to the popular restaurants and a big supermarket you must go up the stairs, which was not easy at all.
Anyway, if you are OK to use earplugs for sleeping and don't care about the view, it will be a good apartment for a good price in the center of Istanbul and close to many touristic attractions.