Again, last time I checked a Mac was a Personal Computer as well.
There really is no difference, I own both...my desktop is windows OS and my laptop is a Mac running OS X 10.5.8.
Everything I do on my Mac laptop, I can do on my windows desktop.
The biggest downside to Mac in my opinion, is there is barely any customization at all, what package you see in the store is basically what you get, with maybe a few minor upgrades, but nothing like you can do with building a windows based pc on newegg....
and someone correct me if I am wrong, but I don't believe you can buy the Macintosh operating system by itself, its not like windows where you can walk into best buy and have your option of standard, office, student, home etc....the only way to get it is by buying one of their computers.