daveloc:
Although Panny explicitly recommend only one model of HDD, other mains-powered USB HDDs often work (I used an old LaCie d2) while bus-powered ones don't. I didn't experience any lockups.
While the system works, and it's useful for e.g., recording the BBC HD Test Card to calibrate the picture, it's operational/ergonomic behaviour is so inferior to that of a dedicated unit such as the Foxsat HDR it would be tedious to list the details. If you schedule recordings, power consumption in standby jumps to 30 watts, and the front power light blinks orange *constantly* and has to be taped over.
You can't watch one channel and record another, or record 2 channels, even if they're from different tuners (i.e., Freesat/Freeview) but you can record while watching from an external input, eg., Bluray, or even an STB.
A useable emergency feature, but not recommendable as even a cheap PVR replacement.
Seems basically like a non-feature really, completely unuseful feature. Marketing gimmick really or feature tack-on maybe.