Our time in Istanbul was excellent, thanks to Tarkan and Julia. The apartment is very beautiful and looks exactly like in the pictures: It's clean, stylish and is equipped with everything you need, e.g. even with a French Press Coffee maker which safed us in the morning :). It's located in what I think is the best area to stay in Istanbul for a city trip. Restaurants, bars, cafés and shops are numerous, if you like walking you won't even need a public transport ticket. Although keep in mind that Istanbul and Galata are very hilly, so when you come back to the apartment in the evening be prepared for a steep walk uphill :).
Despite it's central location, it was not noisy in the night (except for some cat fights :).
The rooftop terrace is a real treasure: You get a wonderful overview of the whole city, especially at night, with the Galata tower right next to you AND you don't even need to stand in line like the people who got to the top of the tower ;).
The communication was always very polite, quick and useful. Julia and Tarkan offer a whole package of services, and I would definitely recommend the airport transport. The driver was very kind and reliable, even as I had to be picked up at 5 AM in the morning.