After years of research on this subject, I have concluded, and this is only my considered judgement, that the MD 500 helicopter is the undisputed winner.
The little pieces of junk are always broken down, can't get parts, and the ones you do get, are of such inferior quality that you wouldn't install them on your car! They are always in need of tracking and balancing, which takes forever, and every engine start is a potential disaster.
My ones thus, consistently make NO noise at all and are therefore ably qualified as the winner!
Unless of course you have a better qualified winner?