I have never like Nutone fans at all. I have installed nothing but Panasonic Fans over the past ten years. I have had a couple complaints about the Panasonic Fan's not working in this time. Both times it was because the client was hard of hearing and could not hear the fan running!
A simple piece of toilet paper stuck to the grill proved the fan works both times.
In a guest powder room near the dining room you might consider a cheaper fan so your guests will have the luxury of that noise if needed!!! I bent the vent grill a little in my guest powder room so it does make more noise - I have always discussed this since we where asked to remove a Panasonic and install a cheaper fan that was louder.
A properly installed Panasonic Fan is very hard to hear when running. We improve the installation with some scrap waterproofing products or sill gasket.