My experience overall was very positive
Pros:
The view was magnificent, probably one of the best views of bosphorus.
The host was very proper and professional, always on time and solving any problems arising instantaneously.
The location was great close to old Istanbul, Karakoy, Taksim, Besiktas, Ortakoy, Cihangir, Nisantasi, all must sees, and any means of public transportation (subway, tramway, boat, bus) was right in front of the house to get to anywhere in Istanbul.
Cons:
There was a frequent reservoir smell from bathroom.
The ceiling height is only around 2 meters. I am 1.75 meter tall but for anyone taller should watch out.