I like my GR Digital III because it has a sharp fast wide angle lens. So much so that I am now thinking seriously about pairing it with a Nikon D300 equipped with a fast medium telephoto such as the 85mm F1.4 AF - this will be the perfect combination of portability and quality.
The recently announced Ricoh GXR camera doesn't excite me at all - in fact I think it is a very silly idea. Ricoh could have made a camera that used the Leica M mount, or even the micro-thirds mount. But to come up with a camera where the body itself has no functionality other than the display, the battery and the menu system is very silly, in my opinion.
The only cost saving it generates is for Ricoh. We as consumers must pay higher cost for the camera and lens combination; and new lenses will be more expensive than they need to be. And as many have pointed out, you do not want your lenses to become obsolete because the sensor attached to them is obsolete.