Mojo might like to give out all the techno babble about wattage and compression and it is total bullshit when it comes to actual sound. You can be right in theory, but never have it happen statistically.
When dynamism is present in a recording, statistically speaking, it will want to be reproduced 100% of the time. If the speakers compress or electronics in the audio chain saturate, the peak will never get reproduced. When this happens, the experience is ruined 100% of the time - statistically speaking. You can see there's a lot of statistics in here, Matt.
I recently reported on this experience and it was an eye-opener for me. I always thought my Onk was so awesome but now I realize it soft-clips at a level far lower than anyone would expect. The reason for the lack of dynamics is puny reserve power.
Now I'll say this. If Justin listens to Metallica: Death Magnetic all day long at 100dB, I agree he can go with M3s. That is so dynamically compressed, there are no peaks.
