quiet, effective, easy.
930253
very quiet, maintains 15' square room (door open) at 35% humidity in dead of winter on low setting.  easy to refill and unobtrusive, somewhat attractive, housing.
2840167
Very sturdy, very simple, does its job quietly and without drawing attention to itself.
729128
Very Quiet and easy to install.  I had an old fan from 1985 that was very small and undersized, the nice thing about this one is that I really didn't have to cut much more out of the existing hole to mount it.  I also liked how It had multiple ways to secure it to a rafter if you couldn't gain access from above.
3506125
Clean, quiet and very effective.  The water storage area is easy to lift, remove and empty.
3558944
This is the second of this model I have installed. The first went in easily, is very effective clearing the bathroom of steam and stale air. And very quiet. Really quiet! So I needed another and didn't think twice about this one. Highly recommended.
1630597
does a very  good job! quiet .  would recommend to a friend.
1585076
This was very easy to install ( I am a contractor) and I was very happy with
how quiet it is.  It could be stronger but for the price I was satisfied.
4504102
Easy to use.  I don't know why some people have said it's noisy, because I find it quieter than the one I had before.  Wish you could see through the door.
1070598
quiet and effective, in this price range, I have not yet found a better fan, it does the job and is easy on the ears. if you have an application that requires an 80mm fan I highly recommend this one.
2324679
Works like a champ, very portable, reasonably quiet, love it.
1845228
Great product. Does as advertised and nice and quiet.
3932458
Wonderfully quiet and variable speed. Works as it should.
3379371
Easy to install and fits perfectly.  Instructions are a little wonky, but once figured out takes less than 10 minutes to install.  Quiet and effective.
2644387
Very Quiet. Very Easy to install. Although I had someone else do the install, but he did it pretty quick. Only a little sheetrock had to be cut. Very Quiet. Almost Zero noise. I find it very efficient. Good Buy.

Edit:
After a while of using, I have decreased this rating. its not powerful. I have a small bathroom, but I don't see it being able to do a good job. Yes its very quiet, but the vapors remain in the bathroom for a long long time.
2156328
Simple, easy to install and use, but effective.
725359
I like how it's pretty quiet, and you can select the exact temperature.  Very easy to use, doesn't have that "space heater smell", it's small, compact, and does the job well!
767668
Excellent value. Very easy to set and use, quiet and efficient.