I enjoyed staying at Özkan's place. The location is just by the Istiklal street, which allows to easily take walks there and to the Galata tower, Galata bridge etc.
Özkan met me the day I arrived, showed how to find the place, was very friendly and caring. Appreciate this!
The appartment is very cozy and has everything you need for a short stay (I stayed for 5 days). Though as it is very close to Istiklal, it has a rock'n'roll bar just below the appartment. On weekend there was some loud music (though live and good) and people chatting outstide the bar. But they stop by 2-3 am so thats fine.
In december it was a bit cold inside, so I'm suggesting bringing some warm home clothes and some home shoes.