I don't have a heavy beard so I can get 7 shaves from a Feather blade. If you despine a GEM blade, they seem to last longer.
I see that the OneBlade blades look approximately the same size as regular DE blades, which suggests to me that they use the same blanks as other Feathers in fabrication.
Can regular blades be used in it? If not, I'd say they're doomed.
Please note that Feather items are only available to UK customers.