Manger Audio Loudspeakers. Has anyone listened to these?

I am particularly fond of full range loudspeakers. I am not terrifically fond of whizzer cone designs because to make them work you have to decouple the main cone from the voice coil at high frequencies, a mechanical crossover.
As I understand it, the Manger driver is a flat Walsh driver. It will cover 120 Hz to 40 kHz! This will just make it down to subwoofer territory. Other full range drivers include Cube Audio and Fostex both of standard construction and both decouple the voice coil from the main cone at higher frequencies. Is this really all that bad or can it be done maintaining high fidelity? I have not heard any of them. Both the Manger and Cube drivers are very expensive, in and around $5000 for a pair. So, I can not afford to experiment. The Fostex is cheap in comparison but it looks well made and specs fine.
I plan on making a pair of open baffle "full range" speakers crossing to subs in and around 100 Hz. Which driver to use?