Don't knock it until you try it
I've had it on my PC about two months now, it works fine.
I was part of the original (alpha?) test group and got invited back to test the beta version - it took them over 12 months to launch the beta trial after the closure of the alpha trials as the beeb had some "governance issues" which had to be resolved.
The DRM issue is a bit of a pain, you get 7-days to download 30 days after the broadcast date to activate the viewing and 7 days to view the file after activating it. But it's better than the alpha version where you only got 7 days after downloading it to view it. The alpha trial also had a planner where you could preview the schedule for up to a week in advance just like on a sky+ and tag content for download - this isn't in the beta version but I'm sure that functionality will be in the full public version.
The alpha trial also had some HDTV content but at the time I didn't have and HDTV and only 1 meg ADSL. Now I've got an HDTV and 16 meg ADSL but they have dropped the HD content on the beta test which is a pity. Hopefully HDTV content will find its way back into the final release version.
It is useful to be able to go back and pull down content you have missed which is exactly what I've done with this weeks top gear (forgot to set the sky+). One of the benefits is that you can pull down some regional programmes as well - BBC Northern Ireland has particularly good nature programes which for some reason don't get aired on the mainland.
On the strength of the alpha test I went out and bought a sky+ (which I use) and also XP media centre (which I don;t use the MCE functionality) as I liked the idea of instant access to recordings.
All in all it's a very good system and similar to what is being used by C4 as "4 on demand". You have to take it for what it is though, which is a system to go back up to a week and watch content you missed or forgot to record - it's not supposed to be a system where what you download is for keeps - if you want one of those Panasonic do a nice freeview HD/DVD recorder or you can always dump from your Sky+ to DVD/PC via scart.
I guess eventually someone will find a way round the DRM issue like they always do in the end.