Artsy people have always preferred Macs, and business people have always been forced to use PCs because they were more compatible in the workplace. In the early days of Apple, they did not license out their software and so there were no clones made ... kind of shot themselves in the cyber foot, like the Sony Betamax deal years ago. IBM once had the only game in town until Apple inspired the PC world to shut off the ugly, yellow DOS screen and use "windows" - yup - Windows95 was essentially Mac 1984! In today's economy, the microsoft industry NEEDS to keep Apple in business to avoid a monopoly, but if phone and tablet sales are any indication ... Windows may just have to watch it's back. The word "phone" is almost synonymous with Apple, as are all the pinch and swipe moves that any 3 yr old can do without training.
There will always be Chevy and Ford, and there will always be Apple and Microsoft ... in fact, the newer Macs can run windows perfectly - they are Intel inside and just need a special bootup to operate just like a pc.
It's a brave new world, and like GM (general Midi) in our industry, the more compatible you are, the longer you'll be on stages. At least ... that's the way I see it.
It's been said earlier in this post - the largest factor is money - Apple is more proprietary and stingy with their knowledge, but everyone copies what they make, and everything they DO make gets sold, so you be the judge - which one will make you the happiest, and do the job for which you buy it?
For me .. it's an Apple a day.