In this first image, you can see the initial location of the pump. Despite the installation instructions which say "fasten to a solid surface," the pump was mounted to the back wall of the under-sink compartment, presumably to save space. This is an internal wall with no studs in the vicinity. The pump itself has rubberized mounting feet but these do not do much good when mounted to an unsupported 1/8" plywood panel. Mechanically and acoustically, this is like mounting the pump to a big drum head. I have not observed significant vibration or hammering of the piping itself but I am not sure I would have heard it over the resonating wall!
My initial test confirms that the result is much quieter. Though I can still hear it, the level is what I expect from a water pump. At a later time, I will consider inserting an accumulator just after the pump in order to reduce the on and off pulsing of the pump that happens at low flow rate.
Update Jan 2014 - Finally decided to add a small accumulator to the pump system. This after getting frustrated with the constant pulsing of the pump which, in turn, was causing the kitchen light to flicker. The addition of the accumulator meant considerable changes to the orientation of the pump and plumbing. This is the result