Well, one neighbor has a RESIDENTIAL generator that is whisper quiet. The issue isn't with generators per se, but with inconsiderate people. My one-year-old woke up every time the damn thing coughed and sputtered under load.
Have to stroll over and have a chat tonight. Knew that sound pressure meter would come in handy for something other than comparing exhausts.
Checked the local code: 57 dB(A) from 7:30AM to 10:00PM, and 52 dB(A) from 10:00 PM to 7:30AM. Seems to me that's pretty quiet.