Revelation Audio Raven would be my choice from your original list. No question. A highly regarded designer who has keenly refined the circuit topology and parts list. These things are important. Nay, critical, essential.
People often refer to the weight of a unit as a sort of shorthand for indicating the quality of the design. And that can be useful. But it is a rather crude measure.
I'd be looking for point to point wiring and the use of 6SN7 tubes or similar (6J5, 6SL7, for instance). These tubes are regarded as classics for a reason. That is, they sound really good.