I totally recommend this place. It looks just the same as in the photos. All of these carpets, paintings, a stove, wooden beds, a stone wall in the main room, a spiral staircase, and beautiful old utensils are wonderful. Districts Balat and Fener are gems on Istambul map, and you can explore them just by stepping out of this house. Your place is located near legendary Cafe Incir, and from the roof terrace you can observe Balat houses, Golden Horn bay, and even Galata Tower.
House interesting and authentic, but you shouldn't expect a lot of comfort. You must fire up the wood stove every night in purpose not to freeze. Water pressure not so big, and not so warm. And we have discussion about extra payment with Mustafa (for second bed, which included), but we make an agreement without further problems.