Although our stay was not the most pleasant one, none of that was directly related to our host or his apartment. The apartment is exactly the same as described, nicely decorated and equiped well enough for a short or medium-long stay. It tends to be quiet and isolated from the street noise, but if you are a light sleeper consider it twice: the floor above is extremely squeeky and you will hear any noise from the stairwell as well (e.g. drunk/horny neighbor)
The guy who assisted with check-in was very kind and helpful. Perfect macro-location, 5-minute walk from Taksim square, Istiklal street, airport bus suhttle, etc. However, we did not like micro-location since the street and neighborhood are still going through fast-moving gentrification process: you will find many hotels and airbnbs there, abut also a lot of dilapidated and unoccupied buildings nearby. We didn't have any inconvenience, but I wouldn't recommend this location to the female traveling alone or going home at 3AM.