There are quite a few PVRs out there at the moment, but only a few have the twin tuner facility which is IMO essential. This website compares most of the current crop of PVRs available. The Dewoo and Sagem models tested on the Gadet show are the same as those on this comparison list but with lager hard drives (250 Gb and 160GB)
http://www.pvrjunction.co.uk/compare/
Having looked at the cheaper models including those from Argos and Aldi ( both only single tuner ) and read a few reviews I went for the Humax and think it's a really good machine, very simple to use and intuitive.
If you find you need to keep your recordings long term though you may be better off getting a DVD recorder with hard drive. This will give you the flexibity to watch programmes in a timeshifted state as well as keeping programmes short term on the hard drive.
Another good place to judge what other users are saying about the machines they own is Digital Spy Forums. Lots of comments about the use and performance of many different PVRs.
http://www.digitalspy.co.uk/forums/forumdispla y.php?s=0a7ce3d21cb5d322e49dfdd246f23d6d&f=90