It really all depends on what you'll be using it for.
The price difference is pretty significant.
If you want to play games and keep it pretty cheap, go for the windows computer.
You can build a pretty decent gaming PC for about $550 dollars where on the Mac side, you can spend over 2,000 dollars and it will play games, but it wont play games as smoothly as the 550 dollar PC.
Don't get me wrong, Macs run great and they run great for a LONG time.
I have had my Mac for a year, and it still runs like it did when I got it.
I also have similar specifications on this Mac as I do on the PC that I built, and yet the Mac has frame rate issues where my PC doesn't (when playing games).
Macs are geared for video editing, making music, web development, and things such as that.
In most cases, they can do everything a PC can do.
Not to mention, the way the operating system is written causes it to not run viruses like windows will.
It's really all up to preference.
I'm not here to say that Mac is superior to Windows.
Both have their pros and their cons.
Just think about what you'll be using it for and what will benefit you more.