Darn P
Said..
Apple systems are currently based upon the Unix platform (with a pretty GUI), do multi-tasking more stable than PCs, take advantage of memory better than Microsoft's current line-up, have a more simple interface, less prone to viruses, have been generally considered better for graphic and audio applications and have much higher software testing requirements before Apple allows release to public.
PC systems - Less cost initially for the same power, have 94% of the current computer market, do better in a network environment, are generally more flexible, have way better gaming system power, have 1000 times more software designed to run on them, more flexible in regards to upgrade paths and hundreds of more choices in regards to hardware and capability.