The 787 is definitely a lot noisier than the 359 and the 388, but as cws rightly says, much less than the 777 or the main deck 744 (upper deck is quieter). I'll admit to have found the 787 a disappointment on the whole and look forward to BA receiving their 359s which I much prefer. Flew the 388 yesterday again which I still like a lot and will be on the 744 in a few days where I always enjoy the UD and (though I know many here don't) for idiosyncratic reasons, the first row of the F cabin.