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"
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