flexy dually vs dual extruder

I’ve been wondering if the flexy dually extruder can print using rigid filament in the flexy portion of the extruder. I’ve read on a authorized Lulzbot distributers page that they have had success printing rigid filament in the flexy part of the flexy dually extruder. My guess is others have tried this and am wondering if one would just bypass the dual extruder and go for the flexy dually if either materials can be used?

Also, would be interested in discussion about the dual extruder on on head vs dual extrusion on separate carriages? The latter is touted as better, but I don’t see an advantage?

Be interested in hearing from those who are experienced.

Rigid filament will wear down the PTFE liner faster. You can do it, you just need to replace parts sooner.

Separate carriages are lower overall mass per carriage, so theoretically faster, but also more expense and complexity usually.

Thanks piercet.
Is there an advantage of a teflon liner over stainless steel?

Well, the Teflon is slippery. That’s the main purpose of it for the flexy extruder. And drilling the guide shape would be complicated in stainless.