I just put in a Broan that had a plastic grill and it looks very nice
to me. I'd prefer the plastic over metal, which, as others have
pointed out, can rust in a bathroom environment. I think it was 2
Sones, and it seems quiet enough for a bathroom to me. One advantage
to having some noise is you can tell it's on from nearby, so it won't
be ase easy to leave it on and forget about it. Of course you could
use a timer to prevent this too.
I had a problem with Air King. Bought one of their fans online based
on the data provided on the spec sheet. The rough in dimensions are
wrong, off by about a 1/2", which screwed me, because in this case, it
was critical and it would not fit.