The three of us stayed at Isik's apartment for 2 weeks. The place has a lot of space. The size of the sofa is good enough for a 180cm (6feet) person to sleep. We were satisfied by all kitchen facilities and bathroom stuff. Hot water was always been. Only internet connection was not so fast especially upload speed (download - up to 10Mbps / upload - up to 1 Mbps).
Yes, terrace is great. We catched wonderful sunsets here. Maybe just few opposite roofs are not so pretty looking. Also there is big umbrella for hot sunny weather.
Location is very cool - easy to go to any direction from Taksim. There are lot of fast food restaurants and small markets on the street which worked most of the time even in lockdown.