You must mean 921 or older, both my 811s are without HDs and are unfortunately not PVRs, I wish. I know a few that have either upgraded from older models or just bought the 942 and I have not heard one of them say it was not FABULOUS.
I am sure you will love it, but you may want to read about this MPEG4 Stuff, while I am not totally up on it, I read that this may even be a need for a NEW HD DVR/PVR but I am sure the smarter people here could answer that. If a Year or 18 months out, maybe you would want to wait?