Handan is great! She's incredibly helpful and her place is fantastic. We were a group of six, so we shared the three double beds and nobody had to sleep on the couch.
The location is perfect, it's on the quiet side of Taksim but very close to Istiklal street and the Nevizade area. Public transport is very close by to go and visit the other many sightseeing spots.
I'd definitely stay at her place again, highly recommended.