Nice stay at Gezi hotel, for three nights in October. The hotel decor is nice, restaurant with a nice view. Location near Taksim Square. The staff was very service minded.
The only down side was a very, very noisy concert right in front of my room balcony on Friday evening (there was a cultural event that weekend). The staff did not inform about this on check in - I learned that a second concert was scheduled for Saturday evening, I asked early in the day to change rooms and they did with no issues. But of course would have avoided a noisy Friday evening had I known, or at least had I been informed it advance I could have planned to be out of my room.
All in all I would go back for the nice decor and location near Taksim - plus the nice staff in spite of the concert issue :)