Apple Macs are a type of personal computers, which notably only ever use one type of motherboard, one graphics card, one sound card etc which results in the operating system being slightly more stable, but you having to pay more for inital hardware and upgrades.
Macs can be used appropriately in media application, like high-end graphic design, video editing or for multitrack recording in recording studios.
As a home PC they are generally less compatible than IBM based PCs, and the extra cost isn't justified for word processing and web browsing.
They are essentially very similar means to the same end - you can do most of the same tasks on both, although they will use different software in the process.