I do not know if this happens only on Ramadan, but at 3 o'clock in the night, a man with a drum was walking in neighborhood to wake up the people for the morning prayer. At 4 o'clock the prayers are heard from the nearby mosque. It was not disturbing from my side, but is better to ask for a room with windows to hotel inner yard.
The booking should be done on hotel web site: at reception the same room will cost you triple!
Staff are eager to help, but, sometime, they are missing basic tourists' information: for example they didn't know what a hop-on hop-off bus can be.
Hotel shuttle from airport is very expensive (60 euro one way), as you can find more convenient one (for example, 20 euro from www.istanbulairportminicab.com).
