We had a fairly nice day in Chicagoland weatherwise yesterday, so I put the Mavic up in my yard to just cycle the batteries and to test out the new props that I got a few weeks ago.....to me they seem very much quieter....!!
they work fine on the original MP1,you will not really benefit from the increased flight time that the MPP has ,as that is mostly down to the ESCs which are different, but as you say they are slightly quieter