But the fact remains that I don’t see how the feature can overcome the fundamental obstacle of being based on an application-centric OS. It might still become a useful addition to my palette of tools, but it certainly will never be able to fully realize the dream of a document-centric or task-centric work environment. And I am also not really sure that only 10% of common user needs require such an environment.

The first blog post you link to is kind of silly in my view… he says Spaces is “broken” because Apple-Tab only switches to a single Space. Of course it does, because Apple-Tab is an application switcher, not a document switcher! What he’s really complaining about is the design of Apple-Tab, not the design of Spaces. Spaces is only incidental to his rant. There is some merit to the argument that Apple-Tab should be a window or document switcher (and I would agree), but since this functionality is provided by good, mature third-party apps (e.g. Peter Maurer’s “Witch”) if one wants it, his complaint is pretty trivial in my view.

Overall, Spaces is the first virtual desktop application I’ve enjoyed using. I’ve tried Virtua Desktops, the Windows PowerToy, and various Unix tools, and most of them were just not well enough integrated for me to use on a regular basis. On the other hand, I’ve been using Spaces consistently since getting Leopard. The zoom in/zoom out metaphor is perfect, being able to drag windows from one space to another is great (yes, many Unix pagers have this, but only in a kind of iconic, small representation, and not live… you can’t zoom out and watch video playing in another space for instance), and I love how if you grab a window you can push it to another space by moving to a screen edge without having to invoke Spaces at all. I also appreciate the speed. Even on my Macbook with integrated graphics, it’s *very* fast… I appreciate that they didn’t take the Virtua desktops approach and add eye-candy like spinning cubes which add latency.

I suspect there will be third party solutions to spreading collections of windows across multiple spaces on application startup. The only applications where this is a big need for me are my web browsers and OmniOutliner, and if you think about the interface requirements for this, it would be a fairly baroque feature to add to the base operating system. As usual, I think Apple’s implementation absolutely nails 90% of common users needs, and does so in a very polished way, leaving the additional bits to third parties.