I love both, but I have to go with McDonald's for the following reasons:
1) I'm eating McDonald's right now
2) I worked there for two years. (NOTE the ED, its past tense

)
3) I prefer the taste of McDonald's (Crispy Chicken, Bacon, No Tomato MMMMMMMMMMMMMMM)
4) I have more respect for McDonald's because, unlike Burger King, they don't have to insult the competition in their commercials so that they can sell a product. (Same deal with Pepsi)