NOT quiet
As a former professional dog groomer I had a couple of large stand dryers with a very long nozzle that allowed me to point it toward the dog I was grooming so that I could hold the dog with one hand and brush with the other. I am amazed that every grooming shop I’ve been into does not have even one of those dryers and that’s why on the rare occasion when  I take my fur babies, they don’t come out looking as well as when I groom them myself! I bought A special stand that strapped in a traditional blow dryer many years ago that allowed me to work basically like the large stand dryer. But my grooming table is in the garage and it’s chilly in the winter time even with the heat lamp.  I was very happy to come across this blow dryer with the built-in brush. Of course it doesn’t work near as well as a pro stand dryer but it is darn close! Especially given the difference in price - hundreds of $$ … -But as far as it being quiet – I don’t think so!! It’s just as noisy as a normal hairdryer .  Hence the 4 stars - don’t advertise something that doesn’t exist! Of course the racket from the dryer scares the pups!  Soooo… I just have one hand to hold the pup and the other to brush with – making it a little trickier than using my little “stand dryer”. And of course it’s much bulkier than just a slicker brush ,making it more difficult to control.
Rating: 4 stars