Michael, the facts of audio technology, which would be confirmed in a properly controlled blind listening test, are that there's no audible difference in either the quality or quantity of power available from those three amplifiers.
Andrew, i think your point to a certain degree touches on the difference in view of myself and John...
I am of the philosophy that a top grade power amp with more than enough power (250-500W per channel) is the ideal route to go.
John is a believer that the amps in receivers today are more than powerful enough to power a HT.
I think the fundamental design of the amp is a large part of the end result, as is the components used. With the comparison of a Class A->A/B there is a fundamental difference in the operation between these two designs, everything else held constant. As you know, the Class A amplifies the entire sign wave, while the A/B only amplifies a % of the sign wave.
In my experience, if a component is built with components with a tolerance of +/- < 1%, the product is going to work pretty damn close to the way the the math works out on the computer modeling. This can only be accomplished at a very high cost.
However, if a manufacture uses components +/- 5% or greater the final product will work, but the real world product will not work exactly as the math says it will due to larger component deviations.
Also, the amps that are hugely over built result in each component within the product working at below rated output. Where the smaller products will result in each component (transistor) working at near max output for the same amount of power (near saturation), as a transistor gets closer to saturation the more noise gets introduced into the circuite, no?
I am not saying either me or John are right or wrong... we just have a fundamental difference of opinion on how to accomplish the same task.
With all of that being said, i honestly can not "hear" a difference between a receiver amp, my Marantz amp, or my Krell amps...... the difference i tell is the available amount of power, the need for more power is the reason i ended up with Krell amps...
The Krell amps use components with +/- .05%-.1% i believe....