First off, those Pioneer watts are deceicving.
They ain't measured the same as the other two. They cheat.
Note, if you will, that the Pioneer rates it's power at 1 khz, an easy point to rate power.
Note also that BOTH the others rate their power at the full 20 - 20khz bandwidts. ...not at the easy to meet 1 khz mark that Pioneer chooses.
Dollars to donuts that if they rated their units at 1 khz, there would not be asignificant difference and conversley, if Pioneer rated it's receiver at the ful bandwidth the others use, it's seemingly impressive power rating would shrink like George Costanza's manhood in cold water.
So, essentially Pioneer is measuring the top speed of it's car going downhill and the others are measuring theirs on level ground.