These have been extensively reviewed, so here are the salient points;
- externally powered
- USB sound input (which utilises the on-board DSP)
- cabled output in case you want to run headphones
- a remote control (which integrates into iTunes)
They are phenomenally clear, with powerful bass which is amazing given the lack of a satellite sub-woofer. They're also attractive and fit in well if you're running any Mac.
A good purchase indeed.