I’ve heard the AGD and they sounded good.
Are they worth the premium price compared to the competition? Have not directly compared so don’t know but having heard many Class Ds including several I own currently, I’d say anything is possible.
Making the circuit look like a vacuum tube is a nice touch both from an aesthetics perspective and surely helps up the appeal to those attached to vacuum tubes that might otherwise be less likely to move on, so an adept marketing move there for sure. Vacuum tubes fascinated me as a child and still do. They are all glowy and I still think they are way cool looking in a 1950’s sci-fi kind of way