I strongly disagree, there is no ONE WAY to correctly design amplifiers, class A, class A/B, mosfets, vaccum tubes, transistors, ecc. The same performance on test bench doesn't implicate they sound the same. In order to "sound" they have to be hooked with speakers, preamplifier and one source. Sound is the result of an interaction.
I quote what I wrote in another thread:
"I think hifi is a system, like a car, that includes the room where it sounds. Consider one element alone would be like consider only engine or brakes or suspension to judge a car. Testing a single element is okay but it will not tell you exactly how it will sounds in your room hooked with your amp, speakers,etc. likewise the results of an engine on test bench will not tell you how it will works a car drives by you on a common road. I was lucky enough to test single gears in my system and often results surprised me."