I'm sure with enough digging around I could find this out for myself, but could someone familiar with things comment on how the performance of these boxes compares to a standard ATI card miner?
High-end ATI cards will do < 1GH/s, with most midrange cards below 500MH/s. This does 5GH/s, while using an essentially an order of magnitude less power than a PC-based rig will use.
The more important specification is the MHash / Joule (also found in the link below). The video says this thing does 5 GHash/s @ 30W. That's 100x the efficiency of the best videocards (1000x if you count the power consumption of the rest of the PC).
https://en.bitcoin.it/wiki/Mining_hardware_comparison