For those who don't like long reviews and want it short: place is great, probably the best view you can get in the whole Istanbul and Simay is a super host! Look for no other place, guaranteed!
For those who want a bit more details :)
Simay is truly amazing host, met and accommodated us in a very friendly way, responded very quickly on all questions and directions needed (especially how to get the apartments, also grocery and restaurants), showed the apartment and explained all the rules. She is paying maximum attention to guests requirements and needs (we didn't need much though but asked few questions and got an immediate reply), communications were super fast and efficient. Overall experience and attitude, approach is great.
About the apartment - it is simply stunning, unbeatable view and panorama over the whole Istanbul, Golden Horn and Bosphorus, the view you will never get tired of any time of the day (especially during sunset!) and you may feel actually jealous you have to leave it to see the city. Living room is large and good for big group, three sofas work well as a beds, apart from two bedrooms with fully equipped beds. All bedlinen was sparkling clean, all required for sleeping was in the apartment, but even there wasn't be sure Simay would supply all needed at no time. Kitchen is big and was supplied with all necessary for comfortable cooking. Despite apartment is located in a place with such a lovely view, it is in the calm part of the city, I would say it was even more quiet than expected and silence was disturbed only few times by rare scooters driving in the streets. Grocery is about 5 min walk, there are also few restaurants around 7-9 min by walk with nice and lovely walk street.
I would like to thank Simay for the accommodation and next time in Istanbul choice of the apartment is obvious. I would personally recommend this place for short or long stays.