The main advantage of the apartment is its location -- I can't imagine having a better one, it's right near Istiklal street with its shops, boutiques and markets. At the same time the apartment is located a bit away from the noisy street to enjoy the peace and quite, but close enough to explore the city center.
There's a nice separate bedroom and a living room combined with a mini kitchen, which is equipped with a kettle, plates and dishes, a small fridge and electric range. We've spent 1,5 month there and we'll definitely stay at Ertan's apartment again when visiting Istanbul :)