I was reading an article about how Leopard looks like Vista. People in the comments got all riled up about the article, attacking each OS. But the real question is: who cares?
Does it really matter who came up with a feature first? If there is something new and revolutionary, the other would be foolish not to add the same feature. Firefox made tabs great, does that mean that nobody else can use them? No. The question at hand is not how did what first, but who does it best?
I don't care if little minutia details are copied from the other operating systems. The only thing that matters is how well each handles it and whether or not that makes a difference. Sure, Linux had "spaces" first, but Macs have other features too and as a whole, it works better than anything else.
Others may be bound to their own expectations. For some people, Windows works better. My sister refuses to use anything apart from Windows, but her criteria for a good computer is different than mine. She values different pieces more or less than I.