Personally, I plan to use this as a mediaplayer, but not for watching movies and TV shows. As an artist who uses video projection in my work, I have waited years for someone to come up with an affordable unit that will allow the level of control generally only possible on a computer -- but in a size that can be easily tucked away.
The most important feature that is possible on a computer, and not possible so far on any media player I know of (except for commercial signage units, which are much too expensive for me) is uninterrupted looping. Lots of media players can be set to loop, although on some it can be hard to figure out how, but I have yet to find one that loops with no break in the image and sound.
Furthermore, using a raspberry pi (or one of the similar types of mini computers currently on the cusp of availability) potentially allows for much more sophisticated interactivity to a video or audio artwork, since add-on boards will allow for sensor inputs, and outputs that could control lights, motors, etc.
These types of possibilities already exist, but never before in quite so small a form and at a price that would allow me to make a whole exhibition full of work for only several hundred dollars rather than several thousand.
If anyone reading this knows of a solution I'm not aware of that has true looping for close to this price, please mention it. I have seen the Moboplay mentioned here -- I'd bet that it doesn't do real looping (the feature list says it does "repeat"). I know about the cu-box, but I'm not yet sure whether it will loop the way I want it to, and I doubt it will have the potential to be interactive in the way I'd like. I know about the allwinner, and I expect that will have similar potential to the pi.