HI Colin,
I agree with you there, Aczel does tend to be allergic to tube amps.
we have to understand that in the early 1990's tube amps were just coming out, and manufacturers were charging HUGE (thousands) dollars for these amps. there was then (surprise!) a lot of snake oil, as there is now too, but now we have a choice, and can get tube amps at a relatively cheapre price of only a few hundred dollars.

However, in one of the older issues, in the letters section, metasonix (he has posted here on ART too, and owns a company that makes guitar amps) tells him that tube amps are not just "tone controls" (non flat frequency curve) but also produce slight amounts of euphonous distortion, and many folsk, like guitar players for example, LOVE this tone of tube amps. Aczel agrees to that in the response to the ltter, and then moves on.

In my opinion, (and I pretty much use SET amps and tube amps in general), tube amps tend to make the music sound better to me.
But I would neve rkid myself that they have higher fidelity than solid state. IN some cases, they may actually "correct" the recording/mastering choices that may make purely reproduced material sound harsh or brittle, and actually make it sound better.

Just my 2 cents.
-akhilesh