Guliz is a wonderful host, as many reviews have also said! The instructions she gave for the flat were great, and it is in a wonderful location close to many coffee shops and transport links. The flat is incredibly clean and tidy, but also a lovely place to come back to after a busy day out and about.
Guliz was also very helpful in pointing out key things to look out for that tourists don't always notice, and googled lots of queries that I had about my stay! She even invited me to see one of her films being screened, it was such an interesting insight into different cultures within Turkey.
My stay in Istanbul would have been a lot less interesting, and I would have learnt a lot less if I'd stayed elsewhere; I'd highly recommend this place :)