I found this quote and had to post it.
"For me the real difference is in the companies behind the games. I have played both and just find that Privateer Press is the girl you want to marry. Games Workshop is the high maintenance super hot girl with the huge entourage. She'll bleed you dry trying to keep up with the latest fashions then break your heart. Privateer Press may not be the most popular or most attractive girl at the party but she won't do you wrong. Not completely without faults but she'll never stop using something you spent money on. In my opinion Warmachine is simply a better game, it's been said before but GW is a miniatures selling company that has a game. Privateer Press is a game company that sells miniatures."