er...
to be frank, as a foreigner, i'm not quite sure whether i can tell them apart in many circumstances...
since the teaching material i've touched, have always put them together = =! 

Actually,I am more familiar with British english.And maybe i don't know the difference between them on earth.

I prefer Amirican  English  ,I think its  accent   more  lovely coz faster.And i like that.

I love British English! But since I lived in America for some time and American accent is easier for me to pick up, I speak English in American accent. It was funny that  the British guy and American girl who worked part-time job with me often complained the other accent to me. British English gives people the sense of royalty, but American English makes people more amiable. 

I prefer British