Uhhh...Its only $120 to upgrade Windows. Don't forget to get Mac OS you have to buy the computer along with it. Apple makes their money from the hardware not the software. Microsoft doesn't sell any hardware. So while Apple can offset the cost, Microsoft does not have that luxury.

* Please do not use "which is better" again. Better is relative to the person, what is better to you is not better for me or someone else. That is how flame wars start.