Hi Peter - welcome to the Forums, and glad you've found us useful!
Re TVs, it's not the case that one model in a range will be the same in all sizes. There are a range of reasons for this:
1) It may be a totally different base panel - made not only in a different factory but even by a different manufacturer. This can, of course, effect quality of end product
2) Different sizes means different competition. For example, a 32- or 37in LCD may be highly rated against its LCD rivals, but its sibling 40- or 52in set may not look so impressive against 42- and 50in plasma rivals - as our reviews are comparative, that could mean a lower star-rating for the larger set.
3) Price. Some manufacturers may go crazy with the pricing of their larger sets, which - as our reviews are also judged on a performance-per-pound criteria - may count against them, compared to better-value rivals
4) Upscaling - large sets have to work harder to upscale SD content/broadcasts, so a manufacturer's engineering is put to a test far more on its bigger sets. A company's upscaling system may produce a superb picture at, say, 32in, but fall down against superior rivals at a larger screen size.
Hope that helps! We are trying to review as many sets as possible, but with manufacturers offering such an insane amount of options, it's not easy.
My best advice, if we haven't covered a particular screen size, is to read our reviews of others in that range, plus rivals at that screen size, then go out and have a good look for yourself (not being afraid to tweak the sets in-store, or to ask to watch your own discs on the TV in question).
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