This is a great read. I really appreciate people, Engineers, Manufacturers, etc. contributing to a well thought out and discussed topic like this one.
I have to say, that I have repaired, serviced, designed, built tube and solid state amplifiers over my ehem..... 45 or more years as an Engineer and I have to say that many people that compare solid state to tube are not comparing apples to apples in terms of specifications on the amps.
Also, most I have encountered do not level match before comparing anything. Then they attribute differences in volume to mean better or worst.
But, I have found that the specifications of transistors do indeed change over the years and usage. Although the amp may work, those transistors are not like new.
Take a 15-20 year old (or older) amp and remove the output transistors. measure the characteristics, then get brand new (if you can find them) same transistors and measure them. Won't be close. Better yet, if you knew or documented the specs of transistors before you put them in the amp, then 20 years later removed them and measured them.... not close to original.
Anyone trying to tell you that transistors don't degrade is no accurate.
But, I have done A/B comparisons of tube vs solid state amps. level matched and similar specs. in the same systems. let me tell you, for excellent tube or solid state amps. I'll take either. They both sound excellent.
And great designers have solved the major distortion problems with solid state amps years ago.
There is some great stuff out there people.
Look at class D now. @athmosphere (Ralph) is right. I can't wait to hear his new Class D amp. He knows people are going to A/B his class D amp with his tube amp to determine if they can decide which is best. For him to market a Class D amp when he spent decades (still do) designing and marketing tube amps, well, it must be worth hearing.
enjoy