I'll start this out by saying that a Pentium 4 is NOT in any way affiliated with a good gaming computer.
my personal thoughts on this
PC's are cheaper but are a better buy if what you are seeking is gaming and doing just everyday stuff. Also good for searching the web. Self upgrades are easy on PC's so there's no need to send it in anywhere you can do it yourself.
Macs are the perfect computer for somebody who arranges photos and records stuff. there are only 3 known viruses for a mac so it's a great computer for surfing the web.
You will be hard pushed to find an un-bias answer.
'Mac' is short for Macintosh, it is the brand name of a company that makes personal computers(PCs).
In general though Macs are called Macs and all other brands are called PCs.
Macs come equipt with the Mac OS (operating system). Whilst PCs can use any OS, most use Windows although there are many others including Ubuntu and Solaris.
PCs are more adjustable than Macs, you can easily add and take things away, install more RAM, remove a drive or install a new OS.
Traditionaly the design industry has stuck firm to Macs and in the early days they were better for handling software and worked closely with the software companie, in essence a Mac was a ready to use design studio. Install the software and your off.
In more recent years though the malleable advantage of PCs has ensured that people can tailor build there PCs to suit there own needs so on that perspective; PCs can be far more suited for design if built to be so.
In short a Mac is an all-rounder
A PC mean while can be an allrounder or it can be a specialist depending on the users needs. It can be specialist at minimal, so if you only want the internet then a cheap PC that has an internet browser is better(economically) than an a Mac or a PC that is designed to play games.