Gobs of power in reserve is where the tone is at. You can pluck harder and the amp does not complain or give up, it just gets louder. You can play LOW notes and the amp just keeps on giving. I used to bridge 1.8Kw with a Chevin A3000 into an Eden 410XLT. Not for the volume, but the authority of the grunt it created was totally the bomb. The modern smaller heads are all very clever with their this that and the other processing. My present amp is DSP-a-go-go, but there is something about a proper big power stage that just delivers. Crest CA9 amps used to be the power amp of choice. Would we choose to carry one @ 21Kg? No chance. Would we love to play through one? Believe it. I guess it is the same kind of power delivered in the big and heavy Aguilar amps which are constantly referred to as having depth and authority.
I am wandering WAY out of my comfort zone now, but a big and hairy power stage is more likely to be able to control cone movement (less flopping around) by having better damping. Please feel free to correct me on this point.
Gobs of power in reserve is where the tone is at.