While debt levels might be lower, Euro nations have a lot more problems in my opinion than the US. Lack of energy independence. Socialist leaning governance. Strong members need to keep weak members of European Union propped up. 

It's also the question that this article raised while comparing US debt with that of EU's. I thought they were just trying to fool people of EU by suggesting their economy is invincible but US is going to fall very soon. And then Euro will become the global currency. 