An interesting thread.
I have a Humax Fox T2 HDD recorder and only the other day was wondering if I will be able to swap the disc when it eventually fails. The reason for doing this is that it is the only HD PVR that I know where it is straightforward to move HD recordings to my laptop for watching when travelling long haul (not that I am doing a lot of that at the moment!). The DRM on all others prevents this, tying recordings to the original Humax motherboard. To learn how to do this, search for Foxy on the hummy.tv website already mentioned.