You're right about the brick (size of toroid). Is that toroid reflective of the power delivered to the speakers? You have to look at the toroid in conjunction with the output components and how they are biased. And it's not about the size of the output caps either. Most don't understand that too much capacitance is not a good thing.
But it's not all about average or dynamic output power. It's about having enough technical knowledge of the audio domain to know how to build those things into the design that will evoke emotion from the listener. Some stuff is very basic that most designers get wrong anyway. Stuff like noise-free design for example. Other stuff is gained by experience - like the use of certain kinds of component materials. It's also about having the time to iterate through research and testing.
It boils down to who do you trust because we really don't have good specs to guide us and anyone can put out a spec sheet in this industry that may not reflect reality.
