Sounds pretty good, doesn’t it?
Just for grins I spent some time and listened to several different video demos of the Sonzera in my studio before replying, however the real test can
only be to play through one and turn the knobs to make it sound more to my own taste.
I also took another listen to demos of other really good 20W amps I'm familiar with to get my bearings.
A big caveat is that the way these amps are set up and miked makes a huge difference. Maybe I'd have done them differently. A video demo comparison has its drawbacks.
Bryan Ewald's demo on the PRS site was by far the best sounding of the Sonzera demos I could find online. I particularly liked the cleans with the 594. It was set up too brittle for my taste with the Silver Sky. But he had the presence cranked way up, and that always seems to bring out the harshness in an amp (speaking only for myself, YMMV).
However, it still sounds like a better buy clean than the Fender '65 Deluxe Reissue, though I preferred the handwired Fender '64 Deluxe reissue. However that one's three times the price. I liked the Sonzera's cleans almost as much as the Cali Tweed 20W, and with a Jensen Blackbird might like the Sonzera as much (the Blackbird is one of my favorite speakers) and preferred the Sonzera to the /13 small Tweed style combo.
I can't fairly comment on the dirty channel, it was set up so differently from the way I'd do it.