We spend 7 days in Kaya's studio, and had a wonderful time there. Kaya responded very fast when we had questions and we went out to eat kebab together which tasted great.
The apartment is looks just like on the pictures and the describtion is very accurate. Only the door to the bathroom doenst close but others have already written about it and if you share a bed with someone, you probably can cope with that as well.
The location is awesome, in a district with enough tourists not to feel lost but with many many locals as well. It is just near the Galata Tower where you have all these small cafés and boutiques as well as the main shops on the shopping street in Istanbul. So the location is great for exploring Istanbul.
A thing which is certainly not the host's fault was that we came home twice with a black out, so no electricity at all for like 2 hours and once where we didnt have any running water. The city is to blame for it but it would have been nice if someone had told us about the water which was apparently planned.
However, the say was great and we would always spend it there again!