They're both good.
Mac's are good for portability, they are very good for messaging, going on facebook and many other things, you can also do your work on bus, train, plane journey's. You can also take them around the world, they are also battery powered, they're less heavy and can easily fit in a laptop bag.
Problems with laptops are... They have far less memory than a PC.
PC's on the other hand, although for the fact they can only go places where there is a plug, they're far more heavy and can't fit in a bag easily, they're also very good for messaging and facebook and all that stuff. You can't take your PC around with you in a bag, it'll be too heavy for you to cope, but the best things about PC's is the fact that... You have a separate keyboard, a separate mouse which is easy to use instead of a trackpad on a mac, PC's also contain far more memory so you don't have to worry so much about saving the work in which you spent time on :) PC's can hold more accessories, they have far more slots than an original Mac
So if I was to choose one... I'd have to choose a PC :)
Hope I helped :D