This was the second time I have stayed at this property (I have also enjoyed a simply excellent "Old Fashioned" at the London Edition) and think it is a great business hotel. It is not a great location for tourists as it its far from many attractions. It is a 10 minute cab ride from the Bosphorus though so which is nice. It is mostly a business district which is perfect for me.
The rooms are large, the staff really make an effort and the spa downstairs is perfect for unwinding after a hard days work.
The only 2 small gripes:
1) They seem to have an issue with their on site dining choices. The first time I went their restaurant Cipriani was closed so you could only eat at the bar. This time the bar was closed and Cipriani was used as the bar with only a limited food menu.
2) It is a long way from the hotel if you happen to hit rush hour. A usual 20 minute taxi ride can take 90 minutes.
Having said that, it is a modern, well furnished and kitted out hotel with excellent staff. I will certainly stay there again when I return to this great city.