The Disposal is very quiet for a 3/4hp motor. The instructions recommend not using plumbers putty.  This is probably accurate if you have a flush mount sink.  Our sink has a flange ring.  Needless to say I had to use plumbers putty to get a seal that didn't leak.  Make sure that you connect the discharge pipe before you mount the Disposal.  I dropped a screw into the plastic housing and had to remove it and get the gasket set screw out.  The Disposal also does not come with a strain relief grommet for the power cord.  It an additional trip to the hardware store was required for this additional part.  It would have been nice if a rubber grommet was provided for the mounting of the power cord.