Hang on - has anyone considered the fact that to watch Freesat while recording another, you'll need two Freesat tuners? Who says the first set of PVRs that come out will have this? And also, it's very possible that you'll see two sorts of Freesat PVR, one with one tuner and one with two - the one with two obviously being more expensive.
So, by going with the PZ81, you'll definitely have one Freesat tuner, that way, you have the option of buying a Freesat PVR with only one Freeview tuner (possibly saving you money when you buy this). Also, if you buy a PVR with two Freesat tuners and the PZ81, you can record two programs at once and watch another channel on your inbuilt PZ81 (something I do on occasions with Freeview).
I'm not trying to persuade you to get the PZ81, I just think this should be considered before you make your choice.