I'm not sure I can answer this question!
Better for what purpose? Gaming? Tweaking? Overclocking? Increased compatibility with the majority of systems? Get a PC. Video/Graphics/Sound? Get a Mac. Anything else? It depends.
While it is true that you will pay a little more for a Mac, you will get that little bit of extra quality as well. Spec out a similar brand-name PC, and I can almost guarantee that the pricing will be similar.
For me it came down to a personal preference thing. I had used PCs for over 15 years before I bought a PowerBook in March. Why? Well, how can I form an informed opinion unless I really do know what I'm talking about? Suffice to say that the Mac is now my main machine, and my PC only gets turned on if I need files off it, or I need to use its DVD burner.
For many people, a PC is a good choice. Their work uses a PC, most people they know use PCs, so it is more familiar. Not everyone is a geek like me
I enjoy the challenge of learning new things, and checking out other computers / OSs etc. I know I'm more productive with my "slower" Mac than many people who use PCs. I also know that in turn many power users on PCs would do more than I do. Why is that? Because (and I say this with monotonous regularity) IMHO the USER is the single biggest factor when determining computer performance (assuming we're not comparing computers built ten years apart or anything).