I have, I'm the owner of a DJIF450 and I can say they're noisy and I don't reckon they will be delivering to places like NewYork due to restrictions. If your houses are well spaced then I recon your neighbors won't mind.
I assume you're running 9 or 10 inch propellers on the F450. I suspect commercial delivery drones would use much larger props, which should be much quieter. That said, even a 9" quad is not going to be very loud 30+ feet in the air. In a populated area, especially one with cars, the noise wouldn't be audible above the ambience.
