RDX? Fail!
Using removable hard disk is a nice and simple idea for backups. But pricing them like they were made of gold is not so nice, since the "bay" is nothing more that a plastic box with a slide for the cartridge to go in, and the cartridge is nothing more than a box with a notebook hard disk in it.
When I first saw them, at an exhibition I thought it was a nice idea, then I asked for the price, and immediately thought it was going to sell about ZERO units for that price. I still use E-SATA or USB2 external hard drives for backup at small offices, and they come for less than half the price of the RDX.