The Messi-Higuain-Aguero-Di Maria attack is the best in the world at the moment. And not just on paper, they cruised through the South American qualifiers and most of the friendlies during the past few years.
They're certainly in the Big Four of candidates along with Brazil, Spain and Germany.
All four have deficiencies. Germany don't have great center forwards or defensive mids, Spain's center forwards and central defenders are suspect, Brazil have freakin' Fred as their starting center forward.
They're still head and shoulders above the rest, though.