If I had no choice but to eat one of them, it would be Burger King hands down, the burgers taste alot better than Mc Donalds ( like it's actually made of real meat ) and everything seems fresher.
But in all honesty, I'd rather eat something else, I think I ate a Burger King a year ago, haven't ate McDonalds in over 2 years, if I'm gonna eat that kind of fast food, I'll get something healthier and tastier that is also actually cheaper ( They're pretty much a rip off in the UK, atleast where I live anyway ).