Hey Dante, there's a pic of it at the link you posted. It's the one with the aluminium base (ring at the bottom) in the pic, the others are clear all the way. So they say the only difference is by excluding the aluminium, it saves money and the Warm Stone and Le version are otherwise identical, with the Le cheaper because of the saving in both manufacture and material. They say the aluminium looks cool but serves no other purpose.
My main issue with what they have done is that they seem to assume all 12AX7s sound the same. As we all know they don't. If you could tweak the circuit to mimic different brands/designs (e.g. long plate vs short plate etc.) it maybe worth trying?? Possibly it word work ok in V2? with the tone created in V1 by a tube of your choice.
Also there is a big difference between what we want our input tubes to do (clip and distort the way only tubes can (around even harmonics)) and what a HiFi buff wants (clean, clear maybe a little warmth). They say [Blind tests show no difference in sound character between WS and vacuum tubes]. This may be so in a HiFi preamp but what about guitar preamp stages?
I'm not sure, based on what's on their site, I'd want to trump up $200 AUD + postage to test them.
The other place they may be ok is poweramp input buffers or phase splitters where you don't necessarily (in our rigs anyway) want to add distortion.