mattfox's answer is typical of a 'PC user', and quite incorrect.
Macs do just as well as Windows PCs at anything at all, and excel is certain areas such as Video editing.
They both use the same hardware, from all sorts of different manufacturers. The difference is that Dell etc. select your components but you're free to choose others to suit your needs; Apple selects everything in the computer and makes sure it all works flawlessly together.
The only real compromise about buying a Mac (except for using software that is windows-only), is that games are far more often written for Windows. This is a historical issue though really, since Macs and Windows PCs have only recently started sharing the same processors (and games are written heavily with the processor in mind, so game writers wrote for the vastly popular format -- Windows).