Apple fanboys. Most people who buy Apple products are fairly ordinary uninformed types. But the people who attract attention are Apple fanboys. They are usually found scouring Web 2 based sites screaming at hacks who they think are writing nasty things about Apple. The usual complaint is that the hack in question works for Microsoft, whereas in their view he should be working for Apple. Deep down they know that Apple products are not worth the cash and are fundamentally insecure. The danger of buying a product is that people might call you an Apple fanboy, by which they mean you are smug git, who thinks that Coldplay are a great band and who cannot get a girlfriend.
Apple costs more. When Steve Jobs moved to Intel chips he was effectively turning his Apple Macs into PCs. The only difference is that the huge price mark up became obvious. While other PC makers, such as Dell do have a high mark up, Apple takes the biscuit. Most of the time it gets away with it because it pitches its products at the high end of the market.
Apple makes its products using partners in China who use child labour and regularly have to be disciplined by Jobs Mob over labour practices.
Apple's build quality. In the 1980s Apples had a nasty habit of catching fire. However during the 1990s the build quality improved and it gained a reputation for reliability while Windows products were full of Blue Screens of Death. However more recently that seems to have slipped dramatically. The recent MacBook Pro had cracked screens and colour problems. In comparison with OS-X, the latest version, Leopard was decidedly buggy.
I just don't like anything about their machines. I was able to buy a tablet PC for the same speed and power as a Mac book pro at a $500 dollar difference and the tablet PC enabled me to draw on the go where the Mac book would have required me to buy an extra wacom tablet. I think I also quoted a Mac tower around $3000 and I ended up building a PC for $900. Macs aren't versatile as a PC.
Each have their own pros and cons for each user. When really at the end of the day both can do pretty much the same computing capabilities. I mean if you were a gamer you would normally buy a PC, but if you were a graphic designer you would probably buy a Mac. Basically though it really comes down to which OS you like better.