Depends what you want to believe. Are you currently unhappy with the volumes you can reach with your current receiver? Are you hearing distortion of sound from clipping because your receiver does not have enough power?
If your current receiver has enough power for you to listen at the volumes you want, more available power won't do anything for you.
I am in a smallish room and don't listen crazy loud,so I have never even come close to using all the power my receiver can put out.