Volkan's place is well located, with Taksim Square being 15minute walk and Istiklal Street being a 10minute walk. The apartment itself has two very nice double beds that can house 2 couples or 2 people and has everything you would need. There is an AC in the main living room which keeps the place cool, though it needs to be kept switched on for a while before the rooms become cool too.
There are shops on the street, 2 minutes away from the flat so any items can purchased from there.
The apartment is located on the 5th floor, access to which is via very steep set of stairs, which makes carrying baggage a little challenging. So it is definitely something to note for someone with mobility issues. We (2 of us) spent minimal time in the apartment as we were out most of the time, however the sofa could have been better as it very small and the cushion kept sliding away but that is a very small complaint.
Volkan was very responsive on Airbnb messaging, especially when I needed access to a pharmacy late at night.
Overall, I would say it is a great place to stay with its strong point being the location.