As a user of OSX, Windows 8, and Linux I have to say:
They're all doing pretty well in the stability department.
I remember the days of Windows hell. I remember pre-OSX Mac, and I've had my share of weird Linux issues. OS X has taken a major nose-dive with Yosemite - I recommend staying on Mavericks. As far as Windows is concerned get over your Start Button issues and just deal with the new interface, it's not that bad and you might like it if you get used to it. As far as Linux is concerned - stop being afraid of it and give it a shot - it's actually easier to keep up to date than Windows is! (though Windows is catching up)