If you want an open machine that allows a great deal of user control and options, go with a PC. If you want a machine which gives you less control, but also less hassles, go with an Apple.
Because Apple tightly controls the software and the hardware, and today is UNIX based, weird timings and compatibility issues rarely exist. They often use standard hardware today, but may modify the ROM of a hard drive to insure it is optimally tuned to work with the particular drive controller it's connected to.
Dell and HP do this on a higher level to insure compatibility and reliability, but have to allow for more OS options, thus increasing the complexity, and possibility of failure.
Apples are more expensive because a great deal of engineering and quality control goes into them. You can build your own more powerful PC for less, but unless you do a great deal of research and understand very low level timings and settings, you're more likely to have some strange glitch or failure that seems completely inexplicable.
The same is true with OSX vs Windows or Linux...the latter two allow for more options, but as a result often do many things, but less of them quite as well as a system tuned for those specific purposes. You also have a lot of contingency code you will probably never need or use, which is also true, but less so, with OSX.
The appeal from a user perspective is that an Apple is generally less hassle to own and use if you only need it to do a few specific things very well. This is why they are generally preferred by professional video and audio editing and production. It's also a highly polished and engineered product.
I like to create on an Apple. I like to play games on a PC.