The Ambassador hotel is at a great location close to all major tourist spots in Istanbul (walking distance from Topkapi Palace, Blue Mosque etc., close to a tram stop to take you to other places). The hotel is in good condition with comfortable beds, nice bathroom. Breakfast is good (not excellent) but the views from the roof terrace over the old city are great. The service by the personnel is excellent. Sanin gave great advice. The only disappointment was the use of the hamam that we reserved for the two of us. It was cold, no steam and the experience was not like a hamam should be. Maybe it was the extremely cold weather (it snowed that evening in Istanbul) that affected the temperature, maybe the masseuse forgot to turn on the hamam, but we had to pour warm water over us to stay warm and even the water turned luke warm at times. We left the hamam before the hour was up, feeling cold and disappointed.
Recommendation: for a Bosporus tour, do not use the 35 Euro organized tour, an inexpensive Turyol tour is just as good.
Advice: when a shoe shiner accidentally drops his brush, do not pick it up and let him persuade you to have a 'free' shoe shine out of gratitude for . It is a scam.