I'm not sure if I would say Mac OS is the best, but it does have the illusion of being most stable, because it's on such a tight hardware platform. When something goes wrong in OS X, it's rarely the software, but the hardware is no better than PC hardware. In fact, the "latest and greatest" for a Mac, is generally a generation behind the latest and greatest for PCs, so from a speed aspect, Mac's speed thrives on the "tried and tested" hardware with developed drivers.
That's not saying Macs are without problems, for example the MacBook Pro's which had nvidia 8xxx chips in them a couple years ago, and the slew of MagSafe problems that have occurred over the years. But that also doesn't even touch the sheer incompetence of the "Geniuses" at the Apple stores.
Story time:
I work at a small computer shop. We don't advertise that we fix Macs, but if a Mac comes in, generally I'm the one who gets to do the work on it, because I'm more familiar with it. A few weeks ago, a fellow came in with a 2010 MacBook Pro 13" model. He said he took it to Apple, when it stopped working, and they replaced the hard drive, copied all his data, and then found that it still wasn't working. After charging him $400 for not doing the job, he came to the shop I work in. He told us that after Apple didn't fix it, they said it could be the logic board. Well, when I looked at it, I determined that it simply couldn't be the logic board. The Mac booted just fine off USB with his new hard drive. So, I dig a little deeper, tear it apart, and decide to order a replacement hard drive/sleep light cable, as it's just one piece. Low and behold, 3 days later when the part arrived, I put his original hard drive back in, pushed the power button, and found that the original problem was a $35 cable. Not an $800 logic board, and not the hard drive, which they charged $400 for.
I sure hope he went and got his money back from Apple, because that kind of service has absolutely no excuses.
So, moral of the story is, if you're that set on going with Apple, you better be really good with computers, or made of money. I always suggest people buy used Macs, because it's still a Mac, just not as overpriced.
http://store.apple.com/us/browse/hom...mco=OTY2ODY3Nw
They put that link all the way at the bottom of store.apple.com, and if you look there's also a Clearance link as well. Apple doesn't like people that use this, but hey, saving money is saving money.
Saying that, yes, I own a MacBook Pro, and I do have plans to buy the latest model, as soon as I can find the configuration I want from a 3rd party vendor. 1 year of Apple Care is good enough for me, because I'd fix it myself if I had to.
Deep down, an Apple is just a computer, running a modified BSD kernel, with a very big price tag. There are much better deals around than Macs.
If you want other Mac horror stories, I have plenty of them.