up there is the NFL. The UEFA Champions League. Also the World Cup as a whole (including confederation qualifiers around the world) and even the Euros are at a similar level.
But I understand that these are typically viewed as tournaments rather than leagues. However, if viewed through that lens, their product is at least as entertaining as the equivalent NFL tournament (the NFL playoffs), IMO.
I agree that the NFL regular season is better than any domestic soccer league. (Although Jeremy is correct is saying that most of the world would disagree).