Its the same as a PACE or SAMSUNG box, except it is a linux based power-PC, which has the ability to link up with your home pc network and interact with the devices to play mp3, stream video, record tv to hard drive, view tv on any pc in house, etc.
Basically it does everything... and if you buy one in 'debug mode' then they are extremely easy to set up. No electronics knowledge required or anything like that - all you need is a few software downloads and a PC to set it all up on.