It's a good choice to stay in Istanbul.
The apartment has almost everything you may need, except microwave :-(, the wasing and drying machines are common for all rooms and located near the entance, so sometimes you need to wait.
Location is good enough. It's not far from subway station. You can reach almost every place in historical center by foot. There are a lot of shops and cafes and retaurants there. It also means a lot of different people :-), the streets are not quiet, but safe enough. But inside the apartment is quiet, you can sleep well if you close windows.
The owner is hospitable, he answers and solves problems quickly and communication was fine.
The price is fair and I think I'd like to stay there again.