Avoiding the meaningless baiting and religious zealotry that brings nothing to this conversation...
I'm a long-time linux user (since pre-1.0 Slackware), but have presentation needs that I personally prefer some software support for. Thus I use a presentation package --- PowerPoint typically. For a long time I would run linux on my laptop and dual-boot windows when I needed to do presentations. The nature of my work and personal preference requires the use of a Unix-based OS to get anything meaningful done.
I first migrated to the Mac when I noticed times had changed and they had built something I had always thought they should do every since they bought the NeXT properties --- tart it up to look sufficiently as they want it to, but leave the Unix underpinnings for the developer/power user crowd (NeXT was great for that --- all the Humanities people I knew that used it had no idea there was a terminal on the machine and loved it...the fact there was a terminal meant I loved it too =). With office available on the Mac, giddy-up - I get the machine I want without dual-booting. Great!
I've always had a worry in the back of my head that my happiness with Macs would be transient --- that as the platform regained traction they would start screwing with it in ways that are unfriendly to the unix crowd. So far, so good, but ever since the iPad I have been concerned they would push toward that being their OS rather than the full-blown OSX we have currently. I do understand the points people make about how developers need a development environment so the desktop OS won't be going anywhere, but that clearly isn't necessarily the case: no reason they can't build a suitable development environment for the more restricted OS, or simply leave it to developers to cross-compile. Bottom line is my utopian "main-stream unix-based OS that is friendly to the non-power user" may well be at risk.
So fine - it's their company, they'll do what they want and probably make oodles of money doing it. But it will ultimately push me back onto linux full-time, and I'll probably just suck it up and learn to live with PDF presentations or OpenOffice as I have no interest in going back to a dual-boot solution...I'm getting too old I guess :).
It will sadden me a little though as in spite of some of the vendor lock-in that Apple tries to encourage, I have been happy using their products and have built up a bit of an ecosystem I enjoy using. I realize I (we?) are not really the market they are concerned with dominating, but it's a shame they jettison the "win-win" product I feel they had in keeping both the unwashed masses and the developer/power user happy with what is available.