Saying "The Empeg Player isn't a mass storage device" is fairly silly, if you ask me. That's what it primarily is - a removable mass storage device. It happens to have a lot of extra cool features and electronics, but in computer terms, it's definitely a mass storage device. It's designed for one fairly specific purpose, yes, but at its heart it's a place to store and retrieve data, and nothing about the design prevents it from storing data other than digital audio. One could buy a second docking station, wipe the software, and have a very expensive but more-or-less standard removable/dockable hard drive.

None of which is to say that it isn't a wonderful gadget - it is. But it's definitely a removable mass storage device.