I'd have to express my preference for neither. Why, you ponder? Because of the people in both countries (and the world, as a matter of fact). Basically, you will find a type of person who is fat, ignorant, idiotic, and self-righteous anywhere, no matter where you choose to reside.
So what if America is overweight? We have a lot of really intelligent and enjoyable people in this country. And Americans say that the English have funny accents and poor hygiene (maybe you don't hear it, but I always hear this...), they're technically pronouncing the words and talking correctly, as they were basically first, and it's hard to believe that they never brush their teeth or take showers.
This whole argument is pointless, as both countries are flawed in many ways. You'll find arrogance anywhere in this world. Considering the fact that I'm used to America, and it's my home, I choose America. (Although I believe the UK is just as pleasant.)