I've stayed in Mustafa Airbnb for just 2 days but I have to say it has everything necessary even for longer stays.
The Airbnb is located on a side of a cool area, full of Hotels and nice Restaurants. It's also close to the main touristic attractions and easy to access public transport from it.
Mustafa is also a great host, always ready to help or make you feel welcome, from small things like finding drinks and tea/coffee in the airbnb to being always available for anything via messages.
In the end, if you're on a budget in Istanbul this is definitely one of the places you can get!