Has anyone used a flex3drive extruder?

Found this on a website looked pretty interesting. Its a flexible shaft extruder so you can still use NinjaFlex and other bendable filament. The motor mass is off the head like the Bowden. But the mechanical parts of pushing the filament into the hotend is next to the hotend. What do you think about the idea? Can it be used for multiple dual or quad hotends?

Here is the address http://mutley3d.com/Flex3Drive/