Not very quiet
Stayed here before flying back to the UK, Saturday night and all we could hear in the room was the wedding in the function rooms below. This did finish at midnight but would have liked to get to sleep earlier. Next morning up with the sun as the LAX Kennel Club is located just behind the hotel and the dogs were barking from sunrise.
If you stay here ask for a room facing the road not the airport (there is very little noise from the planes surprisingly) just noise from everything else.
Staff very pleasant, on the way out we stayed at the Hilton across the road much quieter and a better nights rest.