Rigidity: motion in the x axis is resisted by the primary square frame of composite wood in plane, which is super stiff in that direction. In effect the stops and starts have something firm to push against. In the Y direction the stops and starts are resisted by a very small piece of wood in the bendy direction especially at the front piece where the y idler attaches, hence more oscillation/ringing.

If I'm right ringing might be reduced a good bit by stiffening that y idler mounting piece. I need to test that. I bet it's less of an issue with the original linear bearing I3 version because that piece was doubled up in that design. Anyone who had both care to comment? or are there too many other variables to compare? From what I've read acceleration/jerk/move planning is a bigger factor, though.

I also read somewhere that the more the machine is allowed to move overall during printing the less this happens. An argument for rubber feet.