Good that Staber responds to email directly.
What I think makes the washing action work is that rotating a perforated hexagonal drum inside a hexagonal tub causes a variable clearance between the walls of the former and the latter, forcing water through the load in the drum in a way that's not possible with a cylinder inside a cylinder. And the forced water action, plus the inherent lift-and-drop action of a hexagonal container, would also remove the need for baffles in the drum.
The geometry also explains why the drum capacity is smaller. The maximum size of the drum is always going to be smaller than a comparable cylinder because it has to clear the tub, i.e. the largest dimension of the drum (between opposite vertices) has to clear the smallest dimension of the tub (between opposite parallel walls).
What were Jetcone's problems with the Staber? Or, where can I find the topic thread?
As for me, personally I like to be able to watch what's going on at least during the wash cycle to see that the load is moving and not hung up in some way. If nothing else, to prevent the frustration of doing a load with a lot of pairs of jeans or other difficult items, and getting "done" only to discover some of the stuff has not washed or rinsed adequately. So that rules out all of the top-loading horizontal axis machines for me, because the container has to be closed in such a way as one can't see inside.