The apartment is a funny shape but nicer than depicted in the photos. Bed and sofa were comfortable. Kitchen is sufficient for simple cooking. The apartment would be overpriced but for 1) the location and 2) the balcony (terrace).
1) Great location - a short walk from Sishane metro, Istiklal street, Karakoy and the bridge to Eminou for those comfortable with Istanbul's steep cobbled streets. The street itself is touristy, but parallel and nearby streets are havens of local boutiques and restaurants (Galata Kitchen deserves a particular mention).
2) The little balcony is perfect for two people to enjoy a beverage at the end of the day (it faces east so there's no glare at sunset, however it may stop someone on the sofabed from sleeping well into the morning).