I'm writing this on an iMac. The first computer I used was an Mac, back in '86 and I have used Macs, PCs and various workstations. In my experience, Macs are just as much trouble as PCs, save for the viruses. (I don't think there are any viruses for OS X) Software support is more limited on the Mac than on the PC, but all you need exist if you are prepared to pay for it.
Both are a magnitude better than fifteen years ago and the differences between them are far smaller. Nevertheless, switching between Mac and PC on a daily basis turns you into a cynical computer hater. Small, but important differences, like different keyboard layouts, makes work a pain.
In my experience, Macs age just as fast, if not faster than PCs, but the price of a used Mac is higher than of a used PC. Macs aren't as expensive as they look at first and the design is nice. Or rather, a PC is always more expensive than it looks.
The most commonly used arguments pro and con, like "are more stable" or "easier to use" are in my experience nonsense. Both are about equally hard to use, with a slight edge for Mac if you aren't used to computers. OS X and Windows (NT and later) hardly ever crash, but the applications on both platforms do.
