It's more a problem of attitude and bureucratic mess.
In EU no one is responsible and everyone blames others for the problems while in USA the blaming is not in such way and institutions at least move themselves in some direction.
In EU every country has it's own laws and vote, including most of the monetary stuff. That's like Michigan telling the Fed that they are not OK with printing or doing something with the USD. It's a complete mess because there is no centralized monetary governance.
There is no centralized government in EU... Well, there is one, but they do practically nothing nor have experience how to do it.
So, here you are comparing one strong currency like the USD with a centralized governance since lots of time ago with an uncentralized currency like Euro that has existed 8 years.
It's not that both currencies don't screw up, the difference is that the USA have more than a century of experience about how to manage a centralized currency while EU has no such experience, so they are making beginners mistakes.
In the long run Euro will dissapear or get replaced with something else unless they fix the governing part for that currency.
In USA you have ONE government to blame and that government tends to see the entire USA as ONE big whole. In EU we have more than 25 governments that only see their own territory while they don't care much about the others.
To those who say that Germany and France are seing EU as a whole because they "help" Greece... you should know that France and Germany have more than 100 trillinon/billion (whatever it is the big thing that makes countries go bankrupt... it's too much to be handled) in direct and indirect Greece debts as "investments". If Greece goes out of the Euro or defaults, then France will go bankrupt the next day. So basically, frenchies and germans are trying to save their own asses there... I guess that speculating against your own currency doesn't pay out on the long run
Othewise, how do you explain that 1.5% of the economy can drag down all the rest?