Beatles and Rolling Stones

I am not personally the biggest fan of the Beatles, however I do not mind the Rolling Stones. I feel like the Rolling Stones have a more catchy beat to their music. From listening to some different Beatles songs in my past, I can not get into the rhythm of their beats. Obviously these bands coming from foreign countries took over American Rock n Roll. What is it about these bands that made them so popular compared to other American artists? Was it their looks, voice, lyrics, or instrumental talents?