To reach the apartment from Taksim square, you have to take valleys that are narrow, with a fairly steep slope which was difficult for us, because we had 6 heavy luggages. But the location in sense of closeness to taksim is great.
It was cold inside when the heating (which was central) was off, but Mehmet took care of it every time we asked him to turn it on. Hot water was always available when the heating was on.
Keep in mind that there's no freezer.
The biggest issue for us was the restaurant under the apartment. Every night you could hear smoke, kebab, music, and when there were parties, the people! It wasn't the most quiet neighborhood.
Mehmet was very responsive and took care of our requests every time we contacted him. The apartment felt private and was comfortable.
Overall, we were satisfied and enjoyed our stay.