I was a Niles dealer for over 20 years and found that they made good products, including the DPS-1, albeit a tad pricey.
The 10 Biggest Lies in Audio- Audio Critic magazine:
"2. The Vacuum-Tube Lie
This lie is also, in a sense, about a peripheral matter, since vacuum tubes are hardly mainstream in the age of silicon. It’s an all-pervasive lie, however, in the high-end audio market; just count the tube-equipment ads as a percentage of total ad pages in the typical high-end magazine. Unbelievable! And so is, of course, the claim that vacuum tubes are inherently superior to transistors in audio applications–don’t you believe it.
Tubes are great for high-powered RF transmitters and microwave ovens but not, at the turn of the century, for amplifiers, preamps, or (good grief!) digital components like CD and DVD players. What’s wrong with tubes? Nothing, really. There’s nothing wrong with gold teeth, either, even for upper incisors (that Mideastern grin); it’s just that modern dentistry offers more attractive options. Whatever vacuum tubes can do in a piece of audio equipment, solid-state devices can do better, at lower cost, with greater reliability. Even the world’s best-designed tube amplifier will have higher distortion than an equally well-designed transistor amplifier and will almost certainly need more servicing (tube replacements, rebiasing, etc.) during its lifetime. (Idiotic designs such as 8-watt single-ended triode amplifiers are of course exempt, by default, from such comparisons since they have no solid-state counterpart.)
As for the “tube sound,” there are two possibilities: (1) It’s a figment of the deluded audiophile’s imagination, or (2) it’s a deliberate coloration introduced by the manufacturer to appeal to corrupted tastes, in which case a solid-state design could easily mimic the sound if the designer were perverse enough to want it that way.
Yes, there exist very special situations where a sophisticated designer of hi-fi electronics might consider using a tube (e.g., the RF stage of an FM tuner), but those rare and narrowly qualified exceptions cannot redeem the common, garden-variety lies of the tube marketers, who want you to buy into an obsolete technology."