Unless something has changed, Darwin is *not* Open Source in the OSI sense, ie it is not Free Software (free as in freedom).
Isn't it a BSD-style license? I'm really undecided as to which I feel is 'better', as I find one more ethically acceptable, and the other more economically viable. But then I'm neither an expert on ethics or economics!
Find an x86 machine at the same price as an Apple one and you'll probably find that the performance/features are about equal.
I agree with that wholeheartedly, at least it has been so in the past.
As for freedom, I can't say as i'm in much of a position to go hacking around with any of OS X at the moment, plus, i can run linux on it if I want (SuSE, Debian, Yellow Dog, Mandrake).
I have to say Rob's demo of OS X really made my jaw drop. In terms of functionality,ease of use and integration, it is exactly what people want. I think Linux has a lot to learn from OS X, certainly if anyone wants it to work as a successful desktop OS. I don't think that it's any coincidence that most of the people I have met who use linux are 1)in education/research, 2) hackers (I mean programmers), 3) people who work in technical jobs, network admins etc. 4) people who have *time*.
And I would admit this; if my girlfriend needed to buy a computer, I would recommend an iMac. She is artistic, not technical, she doesn't enjoy hacking computers, and she wants to take it out of the box, connect it up and start using it. Besides which, I can go exploring the BSD underneath when she's not looking ;-)
Of course I wouldn't recommend M$ X-pee-pee.