One of the things that makes these comparisons annoying is the multiple versions of Vista (is Home Premium really comparable to OSX? I don't actually know) I think they do that just so they can have a positive showing on these checklist comparisons, but it ends up hurting the consumer, who has to make uninformed choices and ends up being dependent on slimy salespeople. In addition, developers also have to deal with multiple versions, which must be a support nightmare.

It's a classic example of marketing directives (market segmentation and looking good in these price/feature comparisons) hurting the overall product.