I used PCs from '83 (I was in 8th grade). I even went through a phase when I built my own PCs and spent my free time on comp.os.windows.advocacy.
In '06 I switched to Mac because I was tired of the bugs, crashes, and constant tweaking necessary to get Win to run.
Unlike Vinh, I found the change seamless. I can count on one hand the number of times I've had to resort to Terminal in the past six years. Each time, it's been as easy as Googling the problem and following the solution step by step.
There have certainly been some frustrations along the way, but they've been minor and temporary. I've never been hit with a virus or malware. After switching from MS Office to Apple's Pages, Numbers, and Keynote as my default suite the number of crashes I've experienced has literally dropped to zero. My wife switched a couple of years ago but insists on using Outlook and she's had no end of troubles. There's no doubt in my mind that MS feels a vested interest in making Macs run poorly.
My current MBP is four years old and as much as I'd like a new computer for the heck of it, I honestly cannot think of a single reason to upgrade. After all the travel, bumps, drops, and abuse this computer has taken, it's still like new.