Positives:
It's a modern place, very well equipped with pretty much everything you need. The internet worked perfectly, as did the tv with netflix and all the appliances. They've really made good use of the space. Wiktor was an attentive, responsive host.
Negatives:
It's significantly overpriced. Wiktor has done a good job with the space available but in the end it's still a small groundfloor flat with no view and a bit of a lack of privacy unless you block out all the windows. I've stayed in various airbnbs in Istanbul and by comparison this place is more expensive than it should be. I've just now moved into another place that is two or three times larger, even more well equipped, with bosphorous views and more privacy... and it's 30% cheaper.
If you have to book somewhere at short notice this is not a bad option, but at the current price there are much better spaces available.