I just thought i would add something to this discussion.
Freeview (well, the broadcasters) are adding extra data to the EPG in the next couple of months that is going to make series linking much more reliable. Basically it will allow the box to identify when it has already recorded a particular episode or if it needs to get the repeat etc.
There are also going to be Freeview branded PVR systems released around the same time. I'm sure this will come with some heavy promotion so that people understand that it is an alternative to Sky+.