We had a great stay in Istanbul at Isiks apartment! The apartment is exactly as it looks on the pictures, very clean and every thing you need can be found. It is very central, right next to the metro station, you can be at the airport within 1 hour. You have 2mins walk to the central shopping street and everything in the centre is reachable by foot.
We hope to come back one day, and then we'll just ask for a little bit better weather :)