Has anyboyd used this amp, your thoughts on it

It s too small and low quality  if you want it to last and sound decent go to 

underwood Wally  youhave to spend at-minimum $1000+ 

for example if it cost$1k you are getting less then $200 in parts  the restoverhead and markup.

I've enjoyed a Glow One amplifier for several years in my second system and suggest that you give them a look.

A bit more than the one in the link you posted, but they are hand built with end-to-end wiring and no PC boards and can be found on the secondary market.

Here's the link: https://glow-audio.com/

Enjoy!

The Glow One is a single-end tube amp using one 6BQ5/EL84 per channel at 3.5 watts output. Input/driver tube looks like a 12AT7. I have a similar custom-made amp like it using a 6BG6 pentode for about 7 watts and one 12AT7 driving both output tubes. Nothing new here. These simple circuits were used in table radio's in the 1950's. No feedback and at clipping 5% harmonic distortion.

Such low-power tube amps are better suited for headphones than speakers.

@jond : Since it has one output tube per channel it will of course stay entirely in Class A operation. Class AB requires a pair of tubes/transistors driven by a phase-splitter circuit.