Ok guys/gals...since nobody responded, l bit the bullet and bought one, together with the tube warmer pedal.
Both pieces are well built. Correspondence with Vasili was timely and professional.
I replaced the Rocktron mAxe in my rig with the Colossus preamp.
I haven't spent any time tweaking, but out of the box, it's a high gain face melting machine.
The clean channel sounds amazing.
As soon as time permits, l will tweak some more and update my review.