This may be presumptuous, but I don't think that LawnGnome is trying to say that tube equipment can't sound good, or better than solid-state equipment. I think his point is that, in general, tube equipment tends to add more distortion, thereby decreasing the accuracy of the signal reproduction.
It's possible to argue that some of the better-designed tube gear can be fairly accurate and have high linearity, but it might be said that similar or higher accuracy can be achieved with solid-state equipment for the same price. (Again, speaking only of signal accuracy, not perceived sound quality.)
The usual reason for creating tube equipment seems to be the addition of even-ordered harmonic distortion, which sounds pleasing to the ear... Otherwise, what's the point?
I agree with LawnGnome's philosophy about playback equipment; I don't care what the recording sounded like in the mastering room in the '60s, I care that the sound is accurate, perhaps even more accurate than what the mastering engineer heard. This is the problem with having equipment that is purposefully colored. Sure, some music sounds better with this or that cable, but other music will sound worse. There is no standard to how music is mixed or mastered (now I'm paraphrasing bigshot
), but in my view, playback equipment shouldn't be colored to compensate for the engineers' flaws.
That said, nothing is 100% accurate, and in some ways, coloration in one component can compensate for inaccuracy in another component, or room acoustics. So, completely YMMV.