Supermarkets sell products cheap from faceless factories. Luxor is just a badge name they stick on these sort of boxes. They aren't like a Sony, Panasonic, Humax, Philips etc where there's some decent info on the manufacturers site. What you're going to have to do is buy one and try it, but the old phrase rings true here - "You get what you pay for"
Theres a Luxor one in a big supermarket for £70,
250gig HDD , 2 tuners etc etc.
Would this be okay?
HUMAX PVR9150T - can store about 100hrs worth of TV. Has dual tuners so you can record one channel while watching another from the same box. Or, if your main TV has Freeview then the recorder can record two channels at the same time. It is I believe their entry level model, so discounted to about £120 if you Google.
You can buy a graded box direct from humax. They are fully re-engineered if required but are also shop returns or stock reductions and they are sold with a full guarantee. At the moment they have PVR9150T-G for £89.95 which is an absolute steal at that price.
hth
B