I recently flew A380s from London to Sydney and back, and I certainly noticed how much quieter it was when compared to a 747 and 777. However, the downside to that was that all the incidental noises, such as cutlery clinking, oven doors and trolleys banging in the galley and passengers moving about were therefore far louder in relative terms. My wife found it more difficult to sleep for some of the trip due to this, than on louder aircraft.