You can hear some diesel clatter outside the car, but inside it's much
quieter. Although my current cars are petrol I have been in recent diesels
and they are remarkably quiet. In once case I could hardly believe it
wasn't petrol. Different ballgame to my 1980 W123 200D.
I am not sure I am ready to jump to diesel with my next car (whenever that
might be), but by then there might have been further noticeable progress.
Personally I would not say diesel is the ideal answer for everyone, but it's
become an increasingly interesting proposition not be swept aside because of
old notions about diesel.
NB: To reply directly replace "nospam" with "schmetterling"