The flat was exactly what I expected, even better than its photos. It's a fully renovated flat inside an old building. It was super clean, like a 5-star hotel.
The location is also great; 10-min walk distance from Taksim in the heart of Istanbul and very close to the Bosphorus, Galata, and many other attractions.
The only drawback about the location is that the whole neighborhood is steep, and you have to prepare yourself for soft hiking.
The host is not an individual and is actually a company. They responded to our requests very fast. However, they are very strict on check-in/check-out times and other rules. I asked them to supply more detergent for the washing machine and dishwasher, but they refused (they just put two tablets for the washing machine for one week).
I totally enjoyed my stay and would definitely book it for the next time.