I do get the difference between even ordered harmonics for tube gear being preferred over the odd-ordered harmonics for solid state for sound quality itself. But 2-3% vs say 0.06%?

Here's one I found:

Antique Sound Lab MG-SI15DT Integrated Tube Amplifier - Single Ended, Pure Class A Operation

Rated Power: 5 Watts RMS Per Channel into 8 Ohms in Triode Mode, 15 Watts RMS Per Channel in Tetrode Mode

THD: < 2.5% at 5 Watts, S/N: 78 dB, MFR: 17 Hz - 28 kHz ±1 dB at Full Output, Size: 7 3/4" H x 19" W x 18 1/4" D, Weight: 25 Pounds, MSRP: $699 USA

An admittedly "entry level" tube component, for $700...

Another, more premium one:

http://www.stereophile.com/showarchives.cgi?687:6

See Fig. 3.