Highly recommend the Sultanhan Hotel! We were totally unfamiliar with Istanbul, so we took a chance on this booking and it worked out wonderfully. The location is as stated, walking distance to major destinations, including the Grand Bazaar and Blue Mosque, lots of shops and restaurants nearby, but the hotel itself is on a pretty quiet street and we felt safe in the area. Decent sized room, very clean, great breakfast in the top floor restaurant with amazing views--seriously, no complaints. The staff was very helpful with everything including how to use the excellent (and very close) public transportation, recommendations on things to do, and getting us back to the airport efficiently and relatively cheaply.
Istanbul itself was amazing! The public transportation is cheap, easy to use and dependable. The sights are beautiful; I especially enjoyed our Bosphorus Cruise. Would go back in a heartbeat!