Our Miele is quiet. You have to be standing close to it in the kitchen to know that it is on when it goes through one of its noise cycles. Over five years of seamless operation. It was not an expensive model, and just from perusing opinions, it does seem like the most expensive models of appliances seem to get the most complaints.
I guess the ultra expensive appliances are like British cars (and maybe expensive audio!): if you can afford the car, you should be able to afford the chauffer to fix it or you shouldn't buy it.