Each of my A380 flights (on all 3 airlines flying them) has struck me as being markedly quieter than other aircraft including 744s, also less vibration (which is even more important than noise) and less turbulence. I guess those huge wings help to handle turbulence. But the most significant difference is the pressurization (to 5000 feet instead of 7000); this makes for much less dehydration and noticably less jet lag (for me, at least). I was quite surprised at what a big difference that makes (and of course all pax benefit from this; as will B787 pax as it also will be pressurized to 5000 feet).