New amp being touted as among the best ever......

Ben, no offense but its unlikely that your reviewer has heard all of what might be termed the very best. For example, I know he's not heard one of these:

http://www.atma-sphere.com/products/ma3.html

The fact that an amplifier may or may not 'double down' really says nothing about its sound.

Let's just take a look at that model for a moment- the idea is that the amplifier is a 'voltage source' which is audio engineering shorthand for saying that it can make the same voltage into any load.

This is great if the speaker is designed for that response in an amplifier, and many are. However, the way the human ear hears is a little different from what is on paper. What I mean by that is that the ear perceives amplifier distortion as a tonal coloration.

The reason that is important is thus: In order for an amplifier to double power as impedance is halved (IOW to have a constant voltage characteristic) it has to have transistors in it. Now any transistor has a non-linear capacitive aspect in its junctions (varactor diodes take advantage of this to tune radios). The more current you put through the device the more this is magnified. Usually loop feedback is used to linearize the amplifier, and is enough that this quality of capacitance is taken into account.

The human ear uses the 5th, 7th and 9th harmonics to determine how loud a sound is. When loop feedback is used, these harmonics become artificially enhanced. This causes the amplifier to sound bright and 'shouty'.

Now this is variable with transistor amplifiers; a lot depends on the goal of the designer! But if they focused on making the constant voltage thing work without also paying attention to how our ears work, well then

That depends.

Doesn't it all depend ... on ... lots of things, always?

It goes against my instincts and experience to assume though that there is only one way (tubes) to make tasty audio soup and do the harmonic balance plus all the rest well.

After all, we sent men to the moon years ago. Surely engineers know how to properly apply transistors in SS amplifiers by now as well, especially in the digital age (whoops I used the D word), for those who seek good sound via transistors and not tubes.

Yes, you'd think, but guess what? There is not a lot of engineering talent being applied to the field right now. We've not been to the moon in a long time :)- back then they certainly *did not* know how...