The Buhara Family Inn seemed a great value for Istanbul. My room was small but very clean, good mattress and plenty of hot water. Service was great and the breakfast buffet was excellent with wonderful views of the Blue Mosque and Sea of Marmara from the rooftop terrace.
Just one strong caveat: It is not ideal if you are mobility challenged. The staircases are spirals set in square corners with no handrails on the outside where the steps are wide. The stairs to the terrace are like an old wooden ship's ladder, again with no rails. This is by no means particular to the inn -- Istanbul is full of precarious steps with no handrails -- but if you are not as young as you once were do be advised.
Otherwise, I can't say enough nice things about the place.