I want to start by saying that the stay was ok. The price was ok, maybe a little higher for what it has to offer. So, the value for price was ok, you might find the same ind of apartment for a lower price.
The location of the place is amazing, it's right next to a Mall and the metro station. It is far from what I would consider the main attractions (Grand Bazaar, Galata tower and bridge, Topkapi Palace and so on) but you could easily go there by the metro and/or tram.
The host was nice, BUT the main and most important thing for me as a foreigner in a new country is the communication, and she doesn't speak English AT ALL. She didn't even understand when I was asking her to come downstairs and get me to the apartment, because she gave me a location without the floor number or the number of the apartment or any information of how to get to the apartment, and I just figured she would come downstairs and take us upstairs. I had to run for her to ask for the wifi password, because she didn't understand the first time. She is a nice person though, I had asked her for a vacuum and she got it for me during my stay.
Other than that, the place was ok, a little bit dirty, there was A LOT of dust, especially under the beds and even a used napkin under the bed in the bedroom. There were a couple of Coke bottles in the fridge from the previous owners and some sponges in the shower. The toilet was a little dirty, the floors were a little sticky and there was a used towel in the bathroom.
However, was had what seemed like fresh towels and sheets on the bed. Overall, nice apartment for a couple of days and nice host, if you speak Turkish, but it needs a little bit more attention. There is nothing that would make your stay horrible, but little inconveniences that could have been resolved. :)